Use tcdrain, not fdatasync, to drain ttys

fdatasync is for storage devices, not ttys.
* admin/merge-gnulib (GNULIB_MODULES): Remove fdatasync.
* lib/fdatasync.c, m4/fdatasync.m4: Remove.
* lib-src/Makefile.in (LIB_FDATASYNC):
* src/Makefile.in (LIB_FDATASYNC):
Remove.  All uses removed.
* lib-src/emacsclient.c [!DOS_NT]:
Include <termios.h>, for tcdrain.
* lib-src/emacsclient.c (flush_stdout):
* src/sysdep.c (reset_sys_modes): On ttys, use tcdrain instead
of fdatasync (except don’t use either function if DOS_NT).
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.

2 files changed, 0 insertions, 40 deletions

diff --git a/m4/fdatasync.m4 b/m4/fdatasync.m4
deleted file mode 100644
index fd8e4320d21..00000000000
--- a/m4/fdatasync.m4
+++ /dev/null
@@ -1,32 +0,0 @@
-# fdatasync.m4 serial 4
-dnl Copyright (C) 2008-2018 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-AC_DEFUN([gl_FUNC_FDATASYNC],
-[
-  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
-
-  dnl Using AC_CHECK_FUNCS_ONCE would break our subsequent AC_SEARCH_LIBS
-  AC_CHECK_DECLS_ONCE([fdatasync])
-  LIB_FDATASYNC=
-  AC_SUBST([LIB_FDATASYNC])
-
-  if test $ac_cv_have_decl_fdatasync = no; then
-    HAVE_DECL_FDATASYNC=0
-    dnl Mac OS X 10.7 has fdatasync but does not declare it.
-    AC_CHECK_FUNCS([fdatasync])
-    if test $ac_cv_func_fdatasync = no; then
-      HAVE_FDATASYNC=0
-    fi
-  else
-    dnl Solaris <= 2.6 has fdatasync() in libposix4.
-    dnl Solaris 7..10 has it in librt.
-    gl_saved_libs=$LIBS
-    AC_SEARCH_LIBS([fdatasync], [rt posix4],
-                   [test "$ac_cv_search_fdatasync" = "none required" ||
-                    LIB_FDATASYNC=$ac_cv_search_fdatasync])
-    LIBS=$gl_saved_libs
-  fi
-])
diff --git a/m4/gnulib-comp.m4 b/m4/gnulib-comp.m4
index a4dddbad738..d31dd5d533c 100644
--- a/m4/gnulib-comp.m4
+++ b/m4/gnulib-comp.m4
@@ -81,7 +81,6 @@ AC_DEFUN([gl_EARLY],
   # Code from module faccessat:
   # Code from module fcntl:
   # Code from module fcntl-h:
-  # Code from module fdatasync:
   # Code from module fdopendir:
   # Code from module filemode:
   # Code from module filevercmp:
@@ -241,11 +240,6 @@ AC_DEFUN([gl_INIT],
   fi
   gl_FCNTL_MODULE_INDICATOR([fcntl])
   gl_FCNTL_H
-  gl_FUNC_FDATASYNC
-  if test $HAVE_FDATASYNC = 0; then
-    AC_LIBOBJ([fdatasync])
-  fi
-  gl_UNISTD_MODULE_INDICATOR([fdatasync])
   gl_FUNC_FDOPENDIR
   if test $HAVE_FDOPENDIR = 0 || test $REPLACE_FDOPENDIR = 1; then
     AC_LIBOBJ([fdopendir])
@@ -880,7 +874,6 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/faccessat.c
   lib/fcntl.c
   lib/fcntl.in.h
-  lib/fdatasync.c
   lib/fdopendir.c
   lib/filemode.c
   lib/filemode.h
@@ -1028,7 +1021,6 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/fcntl-o.m4
   m4/fcntl.m4
   m4/fcntl_h.m4
-  m4/fdatasync.m4
   m4/fdopendir.m4
   m4/filemode.m4
   m4/flexmember.m4