Merge from trunk.

diff --cc src/ChangeLog
index 20a6dfca643c0adc9ea3f9c58f48ea483afae550,c3a72f335a1da3c36097542b5c234bc03fbb8da1..cfcb22b5e41ae276cd863ac489344cd7a8b5aae3
--- 1/src/ChangeLog
--- 2/src/ChangeLog
+++ b/src/ChangeLog
@@@ -1,16 -1,15 +1,28 @@@
 +2012-04-14  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.
 +
+ 2012-04-14  Paul Eggert  <eggert@cs.ucla.edu>
+ 
+       Make GC_MAKE_GCPROS_NOOPS the default (Bug#9926).
+       * lisp.h (GC_MARK_STACK): Default to GC_MAKE_GCPROS_NOOPS.
+       * s/cygwin.h, s/darwin.h, s/freebsd.h, s/gnu.h, s/irix6-5.h, s/msdos.h:
+       * s/netbsd.h, s/sol2-6.h:
+       Remove definition of GC_MARK_STACK, since the default now works.
+       * s/aix4-2.h, s/hpux10-20.h, s/unixware.h:
+       Define GC_MARK_STACK to GC_USE_GCPROS_AS_BEFORE, since that's
+       no longer the default.
+       * s/gnu-linux.h (GC_MARK_STACK): Adjust to change in default.
+ 
  2012-04-14  Atsuo Ohki  <ohki@gssm.otsuka.tsukuba.ac.jp>  (tiny change)
  
        * lread.c (lisp_file_lexically_bound_p):