GNU Emacs Installation Guide Copyright (C) 1992, 1994, 1996-1997, 2000-2019 Free Software Foundation, Inc. See the end of the file for license conditions. This file contains general information on building GNU Emacs. For more information specific to the MS-Windows, GNUstep/macOS, and MS-DOS ports, also read the files nt/INSTALL, nextstep/INSTALL, and msdos/INSTALL. For information about building from a repository checkout (rather than a release), also read the file INSTALL.REPO. BASIC INSTALLATION On most Unix systems, you build Emacs by first running the 'configure' shell script. This attempts to deduce the correct values for various system-dependent variables and features, and find the directories where certain system headers and libraries are kept. In a few cases, you may need to explicitly tell configure where to find some things, or what options to use. 'configure' creates a 'Makefile' in several subdirectories, and a 'src/config.h' file containing system-dependent definitions. Running the 'make' utility then builds the package for your system. Building Emacs requires GNU make, . On most systems that Emacs supports, this is the default 'make' program. Here's the procedure to build Emacs using 'configure' on systems which are supported by it. In some cases, if the simplified procedure fails, you might need to use various non-default options, and maybe perform some of the steps manually. The more detailed description in the other sections of this guide will help you do that, so please refer to those sections if you need to. 1. Unpacking the Emacs release requires about 200 MB of free disk space. Building Emacs uses about another 200 MB of space. The final installed Emacs uses about 150 MB of disk space. This includes the space-saving that comes from automatically compressing the Lisp source files on installation. 2a. 'cd' to the directory where you unpacked Emacs and invoke the 'configure' script: ./configure 2b. Alternatively, create a separate directory, outside the source directory, where you want to build Emacs, and invoke 'configure' from there: SOURCE-DIR/configure where SOURCE-DIR is the top-level Emacs source directory. 3. When 'configure' finishes, it prints several lines of details about the system configuration. Read those details carefully looking for anything suspicious, such as wrong CPU and operating system names, wrong places for headers or libraries, missing libraries that you know are installed on your system, etc. If you find anything wrong, you may have to pass to 'configure' one or more options specifying the explicit machine configuration name, where to find various headers and libraries, etc. Refer to the section DETAILED BUILDING AND INSTALLATION below. If 'configure' didn't find some image support libraries, such as Xpm and jpeg, refer to "Image support libraries" below. If the details printed by 'configure' don't make any sense to you, but there are no obvious errors, assume that 'configure' did its job and proceed. 4. Invoke the 'make' program: make 5. If 'make' succeeds, it will build an executable program 'emacs' in the 'src' directory. You can try this program, to make sure it works: src/emacs -Q 6. Assuming that the program 'src/emacs' starts and displays its opening screen, you can install the program and its auxiliary files into their installation directories: make install You are now ready to use Emacs. If you wish to conserve disk space, you may remove the program binaries and object files from the directory where you built Emacs: make clean You can delete the entire build directory if you do not plan to build Emacs again, but it can be useful to keep for debugging. If you want to build Emacs again with different configure options, first clean the source directories: make distclean Note that the install automatically saves space by compressing (provided you have the 'gzip' program) those installed Lisp source (.el) files that have corresponding .elc versions, as well as the Info files. ADDITIONAL DISTRIBUTION FILES * Complex Text Layout support libraries On GNU and Unix systems, Emacs needs the optional libraries "m17n-db", "libm17n-flt", "libotf" to correctly display such complex scripts as Indic and Khmer, and also for scripts that require Arabic shaping support (Arabic and Farsi). On some systems, particularly GNU/Linux, these libraries may be already present or available as additional packages. Note that if there is a separate 'dev' or 'devel' package, for use at compilation time rather than run time, you will need that as well as the corresponding run time package; typically the dev package will contain header files and a library archive. Otherwise, you can download the libraries from . Note that Emacs cannot support complex scripts on a TTY, unless the terminal includes such a support. * intlfonts-VERSION.tar.gz The intlfonts distribution contains X11 fonts in various encodings that Emacs can use to display international characters. If you see a non-ASCII character appear as a hollow box, that means you don't have a font for it. You might find one in the intlfonts distribution. If you do have a font for a non-ASCII character, but some characters don't look right, or appear improperly aligned, a font from the intlfonts distribution might look better. The fonts in the intlfonts distribution are also used by the ps-print package for printing international characters. The file lisp/ps-mule.el defines the *.bdf font files required for printing each character set. The intlfonts distribution contains its own installation instructions, in the intlfonts/README file. * Image support libraries Emacs needs libraries to display images, with the exception of PBM and XBM images whose support is built-in. On some systems, particularly on GNU/Linux, these libraries may already be present or available as additional packages. If there is a separate 'dev' or 'devel' package, for use at compilation time rather than run time, you will need that as well as the corresponding run time package; typically the dev package will contain header files and a library archive. Otherwise, you can download and build libraries from sources. Although none of them are essential for running Emacs, some are important enough that 'configure' will report an error if they are absent from a system that has X11 support, unless 'configure' is specifically told to omit them. Here's a list of some of these libraries, and the URLs where they can be found (in the unlikely event that your distribution does not provide them). By default, libraries marked with an X are required if X11 is being used. libXaw3d https://directory.fsf.org/project/xaw3d/ X libxpm for XPM: http://www.x.org/releases/current/src/lib/ X libpng for PNG: http://www.libpng.org/ libz (for PNG): http://www.zlib.net/ X libjpeg for JPEG: http://www.ijg.org/ X libtiff for TIFF: http://www.remotesensing.org/libtiff/ X libgif for GIF: http://sourceforge.net/projects/giflib/ librsvg2 for SVG: http://wiki.gnome.org/action/show/Projects/LibRsvg If you supply the appropriate --without-LIB option, 'configure' will omit the corresponding library from Emacs, even if that makes for a less-pleasant user interface. Otherwise, Emacs will configure itself to build with these libraries if 'configure' finds them on your system, and 'configure' will complain and exit if a library marked 'X' is not found on a system that uses X11. Use --without-LIB if your version of a library won't work because some routines are missing. * Extra fonts The Emacs distribution does not include fonts and does not install them. On the GNU system, Emacs supports both X fonts and local fonts (i.e. fonts managed by the fontconfig library). If you need more fonts than your distribution normally provides, you must install them yourself. See for a large number of free Unicode fonts. * GNU/Linux development packages Many GNU/Linux systems do not come with development packages by default; they include the files that you need to run Emacs, but not those you need to compile it. For example, to compile Emacs with support for X and graphics libraries, you may need to install the X development package(s), and development versions of the jpeg, png, etc. packages. The names of the packages that you need varies according to the GNU/Linux distribution that you use, and the options that you want to configure Emacs with. On Debian-based systems, you can install all the packages needed to build the installed version of Emacs with a command like 'apt-get build-dep emacs' (on older systems, replace 'emacs' with eg 'emacs25'). On Red Hat-based systems, the corresponding command is 'dnf builddep emacs' (on older systems, use 'yum-builddep' instead). DETAILED BUILDING AND INSTALLATION: (This is for a Unix or Unix-like system. For GNUstep and macOS, see nextstep/INSTALL. For non-ancient versions of MS Windows, see the file nt/INSTALL. For MS-DOS and MS Windows 3.X, see msdos/INSTALL.) 1) See the basic installation summary above for the disk space requirements. 2) In the unlikely event that 'configure' does not detect your system type correctly, consult './etc/MACHINES' to see what --host, --build options you should pass to 'configure'. That file also offers hints for getting around some possible installation problems. 3) You can build Emacs in the top-level Emacs source directory or in a separate directory. 3a) To build in the top-level Emacs source directory, go to that directory and run the program 'configure' as follows: ./configure [--OPTION[=VALUE]] ... If 'configure' cannot determine your system type, try again specifying the proper --build, --host options explicitly. If you don't want X support, specify '--with-x=no'. If you omit this option, 'configure' will try to figure out for itself whether your system has X, and arrange to use it if present. The '--x-includes=DIR' and '--x-libraries=DIR' options tell the build process where the compiler should look for the include files and object libraries used with the X Window System. Normally, 'configure' is able to find them; these options are necessary if you have your X Window System files installed in unusual places. These options also accept a list of directories, separated with colons. To get more attractive menus, you can specify an X toolkit when you configure Emacs; use the option '--with-x-toolkit=TOOLKIT', where TOOLKIT is 'gtk' (the default), 'athena', or 'motif' ('yes' and 'lucid' are synonyms for 'athena'). Compiling with Motif causes a standard File Selection Dialog to pop up when you invoke file commands with the mouse. You can get fancy 3D-style scroll bars, even without Gtk or Motif, if you have the Xaw3d library installed (see "Image support libraries" above for Xaw3d availability). You can tell configure where to search for GTK by giving it the argument PKG_CONFIG='/full/name/of/pkg-config'. Emacs will autolaunch a D-Bus session bus, when the environment variable DISPLAY is set, but no session bus is running. This might be inconvenient for Emacs when running as daemon or running via a remote ssh connection. In order to completely prevent the use of D-Bus, configure Emacs with the options '--without-dbus --without-gconf --without-gsettings'. To read email via a network protocol like IMAP or POP, you can configure Emacs with the option '--with-mailutils', so that it always uses the GNU Mailutils 'movemail' program to retrieve mail; this is the default if GNU Mailutils is installed. Otherwise the Emacs build procedure builds and installs an auxiliary 'movemail' program, a limited and insecure substitute; when this happens, there are several configure options such as --without-pop that provide fine-grained control over Emacs 'movemail' construction. The Emacs mail reader RMAIL is configured to be able to read mail from a POP3 server by default. Versions of the POP protocol older than POP3 are not supported. While POP3 support is typically enabled, whether Emacs actually uses POP3 is controlled by individual users; see the Rmail chapter of the Emacs manual. Unless --with-mailutils is in effect, it is a good idea to configure without POP3 support so that users are less likely to inadvertently read email via insecure channels. On native MS-Windows, --with-pop is the default; on other platforms, --without-pop is the default. For image support you may have to download, build, and install the appropriate image support libraries for image types other than XBM and PBM, see the list of URLs in "Image support libraries" above. (Note that PNG support requires libz in addition to libpng.) To disable individual types of image support in Emacs for some reason, even though configure finds the libraries, you can configure with one or more of these options: --without-xpm for XPM image support --without-jpeg for JPEG image support --without-tiff for TIFF image support --without-gif for GIF image support --without-png for PNG image support --without-rsvg for SVG image support --without-imagemagick for Imagemagick support Use --without-toolkit-scroll-bars to disable Motif or Xaw3d scroll bars. Use --without-xim to inhibit the default use of X Input Methods. In this case, the X resource useXIM can be used to turn on use of XIM. Use --disable-largefile to omit support for files larger than 2GB on systems which support that. Use --without-sound to disable sound support. Use --without-all for a smaller executable with fewer dependencies on external libraries, at the cost of disabling many features. Although --without-all disables libraries not needed for ordinary Emacs operation, it does enable X support, and using the GTK2 or GTK3 toolkit creates a lot of library dependencies. So if you want to build a small executable with very basic X support, use --without-all --with-x-toolkit=no. For the smallest possible executable without X, use --without-all --without-x. If you want to build with just a few features enabled, you can combine --without-all with --with-FEATURE. For example, you can use --without-all --without-x --with-dbus to build with D-Bus support and nothing more. Use --with-wide-int to implement Emacs values with the type 'long long', even on hosts where a narrower type would do. With this option, on a typical 32-bit host, Emacs integers have 62 bits instead of 30. Use --with-cairo to compile Emacs with Cairo drawing. Use --with-modules to build Emacs with support for dynamic modules. This needs a C compiler that supports '__attribute__ ((cleanup (...)))', as in GCC 3.4 and later. Use --enable-gcc-warnings to enable compile-time checks that warn about possibly-questionable C code. This is intended for developers and is useful with GNU-compatible compilers. On a recent GNU system there should be no warnings; on older and on non-GNU systems the generated warnings may still be useful, though you may prefer configuring with --enable-gcc-warnings=warn-only so they are not treated as errors. The default is --enable-gcc-warnings=warn-only if it appears to be a developer build, and is --disable-gcc-warnings otherwise. Use --disable-silent-rules to cause 'make' to give more details about the commands it executes. This can be helpful when debugging a build that goes awry. 'make V=1' also enables the extra chatter. Use --enable-link-time-optimization to enable link-time optimization. With GCC, you need GCC 4.5.0 and later, and 'configure' arranges for linking to be parallelized if possible. With Clang, you need GNU binutils with the gold linker and plugin support, along with the LLVM gold plugin . Link time optimization is not the default as it tends to cause crashes and to make Emacs slower. The '--prefix=PREFIXDIR' option specifies where the installation process should put emacs and its data files. This defaults to '/usr/local'. - Emacs (and the other utilities users run) go in PREFIXDIR/bin (unless the '--exec-prefix' option says otherwise). - The architecture-independent files go in PREFIXDIR/share/emacs/VERSION (where VERSION is the version number of Emacs, like '23.2'). - The architecture-dependent files go in PREFIXDIR/libexec/emacs/VERSION/CONFIGURATION (where CONFIGURATION is the configuration name, like i686-pc-linux-gnu), unless the '--exec-prefix' option says otherwise. The '--exec-prefix=EXECDIR' option allows you to specify a separate portion of the directory tree for installing architecture-specific files, like executables and utility programs. If specified, - Emacs (and the other utilities users run) go in EXECDIR/bin, and - The architecture-dependent files go in EXECDIR/libexec/emacs/VERSION/CONFIGURATION. EXECDIR/bin should be a directory that is normally in users' PATHs. For example, the command ./configure --build=i386-linux-gnu --without-sound configures Emacs to build for a 32-bit GNU/Linux distribution, without sound support. 'configure' doesn't do any compilation or installation itself. It just creates the files that influence those things: './Makefile' in the top-level directory and several subdirectories; and './src/config.h'. When it is done, 'configure' prints a description of what it did and creates a shell script 'config.status' which, when run, recreates the same configuration. If 'configure' exits with an error after disturbing the status quo, it removes 'config.status'. 'configure' also creates a file 'config.cache' that saves the results of its tests to make reconfiguring faster, and a file 'config.log' containing compiler output (useful mainly for debugging 'configure'). You can give 'configure' the option '--cache-file=FILE' to use the results of the tests in FILE instead of 'config.cache'. Set FILE to '/dev/null' to disable caching, for debugging 'configure'. If the description of the system configuration printed by 'configure' is not right, or if it claims some of the features or libraries are not available when you know they are, look at the 'config.log' file for the trace of the failed tests performed by 'configure' to check whether these features are supported. Typically, some test fails because the compiler cannot find some function in the system libraries, or some macro-processor definition in the system headers. Some tests might fail because the compiler should look in special directories for some header files, or link against optional libraries, or use special compilation options. You can force 'configure' and the build process which follows it to do that by setting the variables CPPFLAGS, CFLAGS, LDFLAGS, LIBS, CPP and CC before running 'configure'. CPP is the command which invokes the preprocessor, CPPFLAGS lists the options passed to it, CFLAGS are compilation options, LDFLAGS are options used when linking, LIBS are libraries to link against, and CC is the command which invokes the compiler. By default, gcc is used if available. Here's an example of a 'configure' invocation, assuming a Bourne-like shell such as Bash, which uses these variables: ./configure \ CPPFLAGS='-I/foo/myinclude' LDFLAGS='-L/bar/mylib' \ CFLAGS='-O3' LIBS='-lfoo -lbar' (this is all one shell command). This tells 'configure' to instruct the preprocessor to look in the '/foo/myinclude' directory for header files (in addition to the standard directories), instruct the linker to look in '/bar/mylib' for libraries, pass the -O3 optimization switch to the compiler, and link against libfoo and libbar libraries in addition to the standard ones. For some libraries, like Gtk+, fontconfig and ALSA, 'configure' uses pkg-config to find where those libraries are installed. If you want pkg-config to look in special directories, you have to set PKG_CONFIG_PATH to point to the directories where the .pc-files for those libraries are. For example: ./configure \ PKG_CONFIG_PATH='/usr/local/alsa/lib/pkgconfig:/opt/gtk+-2.8/lib/pkgconfig' 3b) To build in a separate directory, go to that directory and run the program 'configure' as follows: SOURCE-DIR/configure CONFIGURATION-NAME [--OPTION[=VALUE]] ... SOURCE-DIR refers to the top-level Emacs source directory which is where Emacs's configure script is located. 'configure' looks for the Emacs source code in the directory that 'configure' is in. 4) Put into './lisp/site-init.el' or './lisp/site-load.el' any Emacs Lisp code you want Emacs to load before it is dumped out. Use site-load.el for additional libraries if you arrange for their documentation strings to be in the etc/DOC file (see src/Makefile.in if you wish to figure out how to do that). For all else, use site-init.el. Do not load byte-compiled code which was built with a non-nil value of 'byte-compile-dynamic'. It is not a good idea to edit the normal .el files that come with Emacs. Instead, use a file like site-init.el to change settings. To change the value of a variable that is already defined in Emacs, you should use the Lisp function 'setq', not 'defvar'. For example, (setq news-inews-program "/usr/bin/inews") is how you would override the default value of the variable news-inews-program. Before you override a variable this way, *look at the value* that the variable gets by default! Make sure you know what kind of value the variable should have. If you don't pay attention to what you are doing, you'll make a mistake. The 'site-*.el' files are nonexistent in the distribution. You do not need to create them if you have nothing to put in them. 5) Refer to the file './etc/TERMS' for information on fields you may wish to add to various termcap entries. (This is unlikely to be necessary.) 6) Run 'make' in the top directory of the Emacs distribution to finish building Emacs in the standard way. The final executable file is named 'src/emacs'. You can execute this file "in place" without copying it, if you wish; then it automatically uses the sibling directories ../lisp, ../lib-src, ../info. Or you can "install" the executable and the other files into their installed locations, with 'make install'. By default, Emacs's files are installed in the following directories: '/usr/local/bin' holds the executable programs users normally run - 'emacs', 'etags', 'ctags', 'emacsclient'. '/usr/local/share/emacs/VERSION/lisp' holds the Emacs Lisp library; 'VERSION' stands for the number of the Emacs version you are installing, like '23.1' or '23.2'. Since the Lisp library changes from one version of Emacs to another, including the version number in the path allows you to have several versions of Emacs installed at the same time; in particular, you don't have to make Emacs unavailable while installing a new version. '/usr/local/share/emacs/VERSION/etc' holds the Emacs tutorial, the DOC file, and other architecture-independent files Emacs might need while running. '/usr/local/libexec/emacs/VERSION/CONFIGURATION-NAME' contains executable programs used by Emacs that users are not expected to run themselves. 'VERSION' is the number of the Emacs version you are installing, and 'CONFIGURATION-NAME' is the value deduced by the 'configure' program to identify the architecture and operating system of your machine, like 'i686-pc-linux-gnu' or 'sparc-sun-sunos'. Since these files are specific to the version of Emacs, operating system, and architecture in use, including the configuration name in the path allows you to have several versions of Emacs for any mix of machines and operating systems installed at the same time; this is useful for sites at which different kinds of machines share the file system Emacs is installed on. '/usr/local/share/info' holds the on-line documentation for Emacs, known as "info files". Many other GNU programs are documented using info files as well, so this directory stands apart from the other, Emacs-specific directories. '/usr/local/share/man/man1' holds the man pages for the programs installed in '/usr/local/bin'. Any version of Emacs, whether installed or not, also looks for Lisp files in these directories. '/usr/local/share/emacs/VERSION/site-lisp' holds the local Emacs Lisp files installed for Emacs version VERSION only. '/usr/local/share/emacs/site-lisp' holds the local Emacs Lisp files installed for all Emacs versions. When Emacs is installed, it searches for its Lisp files in '/usr/local/share/emacs/VERSION/site-lisp', then in '/usr/local/share/emacs/site-lisp', and finally in '/usr/local/share/emacs/VERSION/lisp'. If these directories are not what you want, you can specify where to install Emacs's libraries and data files or where Emacs should search for its Lisp files by giving values for 'make' variables as part of the command. See the section below called 'MAKE VARIABLES' for more information on this. 7) Check the file 'dir' in your site's info directory (usually /usr/local/share/info) to make sure that it has a menu entry for the Emacs info files. 8) If your system uses lock files to interlock access to mailer inbox files, and if --with-mailutils is not in effect, then you might need to make the Emacs-specific 'movemail' program setuid or setgid in order to enable it to write the lock files. We believe this is safe. 9) You are done! You can remove executables and object files from the build directory by typing 'make clean'. To also remove the files that 'configure' created (so you can compile Emacs for a different configuration), type 'make distclean'. MAKE VARIABLES You can change where the build process installs Emacs and its data files by specifying values for 'make' variables as part of the 'make' command line. For example, if you type make install bindir=/usr/local/gnubin the 'bindir=/usr/local/gnubin' argument indicates that the Emacs executable files should go in '/usr/local/gnubin', not '/usr/local/bin'. Here is a complete list of the variables you may want to set. 'bindir' indicates where to put executable programs that users can run. This defaults to /usr/local/bin. 'datadir' indicates where to put the architecture-independent read-only data files that Emacs refers to while it runs; it defaults to /usr/local/share. We create the following subdirectories under 'datadir': - 'emacs/VERSION/lisp', containing the Emacs Lisp library, and - 'emacs/VERSION/etc', containing the tutorials, DOC file, etc. 'VERSION' is the number of the Emacs version you are installing, like '23.1' or '23.2'. Since these files vary from one version of Emacs to another, including the version number in the path allows you to have several versions of Emacs installed at the same time; this means that you don't have to make Emacs unavailable while installing a new version. 'libexecdir' indicates where to put architecture-specific data files that Emacs refers to as it runs; it defaults to '/usr/local/libexec'. We create the following subdirectories under 'libexecdir': - 'emacs/VERSION/CONFIGURATION-NAME', containing executable programs used by Emacs that users are not expected to run themselves. 'VERSION' is the number of the Emacs version you are installing, and 'CONFIGURATION-NAME' is the value deduced by the 'configure' program to identify the architecture and operating system of your machine, like 'i686-pc-linux-gnu' or 'sparc-sun-sunos'. Since these files are specific to the version of Emacs, operating system, and architecture in use, including the configuration name in the path allows you to have several versions of Emacs for any mix of machines and operating systems installed at the same time; this is useful for sites at which different kinds of machines share the file system Emacs is installed on. 'infodir' indicates where to put the info files distributed with Emacs; it defaults to '/usr/local/share/info'. 'mandir' indicates where to put the man pages for Emacs and its utilities (like 'etags'); it defaults to '/usr/local/share/man/man1'. 'prefix' doesn't give a path for any specific part of Emacs; instead, its value is used to determine the defaults for all the architecture-independent path variables - 'datadir', 'sharedstatedir', 'infodir', and 'mandir'. Its default value is '/usr/local'; the other variables add on 'lib' or 'man' to it by default. For example, suppose your site generally places GNU software under '/usr/users/software/gnusoft' instead of '/usr/local'. By including 'prefix=/usr/users/software/gnusoft' in the arguments to 'make', you can instruct the build process to place all of the Emacs data files in the appropriate directories under that path. 'exec_prefix' serves the same purpose as 'prefix', but instead determines the default values for the architecture-dependent path variables - 'bindir' and 'libexecdir'. The above variables serve analogous purposes in the makefiles for all GNU software; the following variables are specific to Emacs. 'archlibdir' indicates where Emacs installs and expects the executable files and other architecture-dependent data it uses while running. Its default value, based on 'libexecdir' (which see), is '/usr/local/libexec/emacs/VERSION/CONFIGURATION-NAME' (where VERSION and CONFIGURATION-NAME are as described above). 'GZIP_PROG' is the name of the executable that compresses installed info, manual, and .el files. It defaults to gzip. Setting it to the empty string suppresses compression. Remember that you must specify any variable values you need each time you run 'make' in the top directory. If you run 'make' once to build emacs, test it, and then run 'make' again to install the files, you must provide the same variable settings each time. To make the settings persist, you can edit them into the 'Makefile' in the top directory, but be aware that running the 'configure' program erases 'Makefile' and rebuilds it from 'Makefile.in'. The path for finding Lisp files is specified in src/epaths.h, a file which is generated by running configure. To change the path, you can edit the definition of PATH_LOADSEARCH in that file before you run 'make'. The top-level Makefile stores the variable settings it used in the Makefiles for the subdirectories, so you don't have to specify them when running make in the subdirectories. PROBLEMS See the file './etc/PROBLEMS' for a list of various problems sometimes encountered, and what to do about them. This file is part of GNU Emacs. GNU Emacs is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. GNU Emacs is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Emacs. If not, see .