Merge from origin/emacs-27

75723ec212 (origin/emacs-27) ; * lisp/emacs-lisp/benchmark.el (benchm...
53e2a612ad ; * lib-src/make-fingerprint.c: Update commentary.
286c632772 Reformat argument commentary in etags.c
4ec740866a Make the invocation of combine-change-calls in comment-reg...
66bcec8838 * lisp/progmodes/cc-langs.el (c-<>-notable-chars-re): Fix ...
03eeab469e ; Update the expected result files in test/manual/etags.
d875a22bc6 Update the various INSTALL files

# Conflicts:
#	INSTALL

1 files changed, 17 insertions, 11 deletions

diff --git a/INSTALL b/INSTALL
index e880b4e3547..5909e8c9fcf 100644
--- a/INSTALL
+++ b/INSTALL
@@ -117,19 +117,25 @@ 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 <https://www.nongnu.org/m17n/>.
+On GNU and Unix systems, Emacs needs optional libraries to correctly
+display such complex scripts as Indic and Khmer, and also for scripts
+that require Arabic shaping support (Arabic and Farsi).  If the
+HarfBuzz library is installed, Emacs will build with it and use it for
+this purpose.  HarfBuzz is the preferred shaping engine, both on Posix
+hosts and on MS-Windows, so we recommend installing it before building
+Emacs.  The alternative for GNU/Linux and Posix systems is to use the
+"m17n-db", "libm17n-flt", and "libotf" libraries.  (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.  On MS-Windows, if HarfBuzz is not available, Emacs
+will use the Uniscribe shaping engine that is part of the OS.
 
 Note that Emacs cannot support complex scripts on a TTY, unless the
-terminal includes such a support.
+terminal includes such a support.  However, most modern terminal
+emulators, such as xterm, do support such scripts.
 
 * intlfonts-VERSION.tar.gz