Revert last change to gmalloc.c; update some comments.

ChangeLog

+2013-08-15  Ken Brown  <kbrown@cornell.edu>
+
+	* configure.ac (G_SLICE_ALWAYS_MALLOC): Update comment.
+
 2013-08-15  Glenn Morris  <rgm@gnu.org>
 
 	* make-dist: Do not distribute etc/refcards TeX intermediate files.

configure.ac

@@ -4340,14 +4340,16 @@ fi
 
 
 case $opsys in
-  dnl Emacs supplies its own malloc, but glib (part of Gtk+) calls
-  dnl memalign and on Cygwin, that becomes the Cygwin-supplied memalign.
-  dnl As malloc is not the Cygwin malloc, the Cygwin memalign always
-  dnl returns ENOSYS.  A workaround is to set G_SLICE=always-malloc. */
+  dnl Emacs supplies its own malloc, but glib calls posix_memalign,
+  dnl and on Cygwin prior to version 1.7.24 that becomes the
+  dnl Cygwin-supplied posix_memalign.  As malloc is not the Cygwin
+  dnl malloc, the Cygwin posix_memalign always returns ENOSYS.  A
+  dnl workaround is to set G_SLICE=always-malloc.  This is no longer
+  dnl needed starting with cygwin-1.7.24, and it is no longer
+  dnl effective starting with glib-2.36. */
   cygwin)
     AC_DEFINE(G_SLICE_ALWAYS_MALLOC, 1, [Define to set the
-      G_SLICE environment variable to "always-malloc" at startup, if
-      using GTK.])
+      G_SLICE environment variable to "always-malloc" at startup.])
     ;;
 
   hpux11)

src/ChangeLog

+2013-08-15  Ken Brown  <kbrown@cornell.edu>
+
+	* emacs.c (main): Update comment about G_SLICE_ALWAYS_MALLOC.
+	* gmalloc.c (memalign) [CYGWIN]: Revert last change; it's not
+	needed.
+
 2013-08-15  Paul Eggert  <eggert@cs.ucla.edu>
 
 	Fix minor problems found by static checking.

src/emacs.c

@@ -696,7 +696,8 @@ main (int argc, char **argv)
 #endif
 
 #ifdef G_SLICE_ALWAYS_MALLOC
-  /* This is used by the Cygwin build.  */
+  /* This is used by the Cygwin build.  It's not needed starting with
+     cygwin-1.7.24, but it doesn't do any harm.  */
   xputenv ("G_SLICE=always-malloc");
 #endif
 

src/gmalloc.c

@@ -1558,15 +1558,6 @@ License along with this library.  If not, see <http://www.gnu.org/licenses/>.  *
 
 void *(*__memalign_hook) (size_t size, size_t alignment);
 
-/* As of version 1.7.24, Cygwin allows applications to provide their
-   own posix_memalign (but not memalign).  But posix_memalign as
-   defined in this file calls memalign, so we have to rename the
-   latter in order to make sure that posix_memalign calls Emacs's
-   memalign.  */
-#ifdef CYGWIN
-#define memalign emacs_memalign
-#endif
-
 void *
 memalign (size_t alignment, size_t size)
 {