Merge from trunk.

diff --cc ChangeLog
index 99ce37a2fee3ff6f795bc8552fcb1f876d392155,a7da9e1ad5bd593bb1922cff5300af773f181e40..6020d15779756ff598215281eaa1d9baa953b25c
--- 1/ChangeLog
--- 2/ChangeLog
+++ b/ChangeLog
@@@ -1,20 -1,14 +1,31 @@@
- 2012-04-14  Paul Eggert  <eggert@cs.ucla.edu>
++2012-04-17  Paul Eggert  <eggert@cs.ucla.edu>
 +
 +      configure: new option --enable-gcc-warnings (Bug#11207)
 +      I have been using this change for many months in my private copy
 +      of Emacs, and have used it to find several bugs.  It's mature
 +      enough to publish now.
 +      * Makefile.in (GNULIB_MODULES): Add warnings, manywarnings.
 +      * configure.in: Support --enable-gcc-warnings, in the style of
 +      other GNU packages such as coreutils.
 +      (C_WARNINGS_SWITCH): Remove, replacing with...
 +      (WARN_CFLAGS, GNULIB_WARN_CFLAGS): New variable.
 +      (PKG_CHECK_MODULES, C_SWITCH_X_SITE): Use -isystem rather than -I,
 +      when including system files with GCC.
 +      * etc/NEWS: Mention --enable-gcc-warnings.
 +      * lib/Makefile.am (AM_CFLAGS): New macro.
 +      * m4/manywarnings.m4, m4/warnings.m4: New files, from gnulib.
 +
+ 2012-04-17  Dmitry Antipov  <dmantipov@yandex.ru>
+ 
+       * configure.in (AC_CHECK_FUNCS):
+       Add getpwent, endpwent, getgrent, endgrent. (Bug#7900)
+ 
+ 2012-04-16  Glenn Morris  <rgm@gnu.org>
+ 
+       * configure.in (NS_HAVE_NSINTEGER): Remove unnecessary variable.
+ 
+       * configure.in: Remove X libs workaround for old autoconf.
+ 
  2012-04-12  Ken Brown  <kbrown@cornell.edu>
  
        * configure.in: Warn that Cygwin 1.5 is unsupported.  (Bug#10398)

diff --cc configure.in
Simple merge

diff --cc etc/NEWS
index 27b5406a155c50320a8693907fed3234d6e9167d,0d8c145b362aa3ff497e2eb0fed130ada5be8fdd..16b9f75c5039764ce3e7d3f8004b190846b4db41
--- 1/etc/NEWS
--- 2/etc/NEWS
+++ b/etc/NEWS
@@@ -22,13 -22,6 +22,13 @@@ so we will look at it and add it to th
  
  \f
  * Installation Changes in Emacs 24.2
- may or may not be useful.  By default, these warnings are not generated.
 +
 +** New configure option '--enable-gcc-warnings', intended for developers.
 +If building with GCC, this enables compile-time checks that warn about
 +possibly-questionable C code.  On a recent GNU system there should be
 +no warnings; on older and on non-GNU systems the generated warnings
++may be useful.
 +
  \f
  * Startup Changes in Emacs 24.2
  

diff --cc lib-src/ChangeLog
index 55e76c0b0080b00d056a7af6ea2ef0eb90ca5787,ea5f5a2662796092c11873f0c5b723b97ab5394e..161d71381c0406386b1bf242b8acdcad0393ed2b
--- 1/lib-src/ChangeLog
--- 2/lib-src/ChangeLog
+++ b/lib-src/ChangeLog
@@@ -1,10 -1,3 +1,10 @@@
- 2012-04-16  Paul Eggert  <eggert@cs.ucla.edu>
++2012-04-17  Paul Eggert  <eggert@cs.ucla.edu>
 +
 +      configure: new option --enable-gcc-warnings (Bug#11207)
 +      * Makefile.in (C_WARNINGS_SWITCH): Remove.
 +      (WARN_CFLAGS, WERROR_CFLAGS): New macros.
 +      (BASE_CFLAGS): Use new macros rather than old.
 +
  2012-04-16  Paul Eggert  <eggert@cs.ucla.edu>
  
        Assume less-ancient POSIX support.

diff --cc lwlib/ChangeLog
index 85b69f47d28690c75b2750bb6dcf1317c3d67771,8ac9e6994ab5fc92503cdcfe890dec4e6b1fe637..f6ffedeafda38a4f7a2aa019927cd0fb25559a14
--- 1/lwlib/ChangeLog
--- 2/lwlib/ChangeLog
+++ b/lwlib/ChangeLog
@@@ -1,10 -1,3 +1,10 @@@
- 2012-04-14  Paul Eggert  <eggert@cs.ucla.edu>
++2012-04-17  Paul Eggert  <eggert@cs.ucla.edu>
 +
 +      configure: new option --enable-gcc-warnings (Bug#11207)
 +      * Makefile.in (C_WARNINGS_SWITCH): Remove.
 +      (WARN_CFLAGS, WERROR_CFLAGS): New macros.
 +      (ALL_CFLAGS): Use new macros rather than old.
 +
  2012-04-11  Glenn Morris  <rgm@gnu.org>
  
        * Makefile.in (C_SWITCH_X_SYSTEM): Remove.

diff --cc msdos/ChangeLog
index fa7dc23471708e96516c1bd4f9b0875f5f7cbfc6,320d2f5e6c199b9626d7f0f3dc83ba838bd36cac..bf3a11d5bd875d81312e288edc0615da4a349980
--- 1/msdos/ChangeLog
--- 2/msdos/ChangeLog
+++ b/msdos/ChangeLog
@@@ -1,9 -1,3 +1,9 @@@
- 2012-04-14  Paul Eggert  <eggert@cs.ucla.edu>
++2012-04-17  Paul Eggert  <eggert@cs.ucla.edu>
 +
 +      configure: new option --enable-gcc-warnings (Bug#11207)
 +      * sed1v2.inp, sed3v2.inp, sedlibmk.inp: GNULIB_WARN_CFLAGS,
 +      WARN_CFLAGS, and WERROR_CFLAGS replace C_WARNINGS_SWITCH.
 +
  2012-04-11  Glenn Morris  <rgm@gnu.org>
  
        * sedlibmk.inp, sed1v2.inp: GNUSTEP_CFLAGS replaces C_SWITCH_X_SYSTEM.

diff --cc oldXMenu/ChangeLog
index a76ea61abd8243c7d56c6bb4cc6d806167bfd5d5,5b86ccec21e8798696e2d9518a799f24d45a09a5..243899e011d9385f5c302ed5992269841f700c92
--- 1/oldXMenu/ChangeLog
--- 2/oldXMenu/ChangeLog
+++ b/oldXMenu/ChangeLog
@@@ -1,10 -1,3 +1,10 @@@
- 2012-04-14  Paul Eggert  <eggert@cs.ucla.edu>
++2012-04-17  Paul Eggert  <eggert@cs.ucla.edu>
 +
 +      configure: new option --enable-gcc-warnings (Bug#11207)
 +      * Makefile.in (C_WARNINGS_SWITCH): Remove.
 +      (WARN_CFLAGS, WERROR_CFLAGS): New macros.
 +      (ALL_CFLAGS): Use new macros rather than old.
 +
  2012-04-11  Glenn Morris  <rgm@gnu.org>
  
        * Makefile.in (C_SWITCH_X_SYSTEM): Remove.

diff --cc src/ChangeLog
index 7362bf462a9af5bdd617b9c4bf86961681862574,8c0dcc9c0442492d8a3aa67a26dcf003094cb015..78fa3b501a38083159de162ce373c54811da8c51
--- 1/src/ChangeLog
--- 2/src/ChangeLog
+++ b/src/ChangeLog
@@@ -1,3 -1,12 +1,25 @@@
++2012-04-17  Paul Eggert  <eggert@cs.ucla.edu>
++
++      configure: new option --enable-gcc-warnings (Bug#11207)
++      * Makefile.in (C_WARNINGS_SWITCH): Remove.
++      (WARN_CFLAGS, WERROR_CFLAGS): New macros.
++      (ALL_CFLAGS): Use new macros rather than old.
++      * process.c: Ignore -Wstrict-overflow to work around GCC bug 52904.
++      * regex.c: Ignore -Wstrict-overflow.  If !emacs, also ignore
++      -Wunused-but-set-variable, -Wunused-function, -Wunused-macros,
++      -Wunused-result, -Wunused-variable.  This should go away once
++      the Emacs and Gnulib regex code is merged.
++      (xmalloc, xrealloc): Now static.
++
+ 2012-04-17  Glenn Morris  <rgm@gnu.org>
+ 
+       * dired.c (Fsystem_users): Doc fix.
+ 
+ 2012-04-17  Dmitry Antipov  <dmantipov@yandex.ru>
+ 
+       * dired.c (Fsystem_users, Fsystem_groups): New functions.  (Bug#7900)
+       (syms_of_dired): Add them.
+ 
  2012-04-16  Paul Eggert  <eggert@cs.ucla.edu>
  
        Fix minor alloc.c problems found by static checking.