Improve MS-Windows related commentary and log entry for 2012-08-19T21:00:09Z!eggert@cs.ucla.edu.

src/ChangeLog

@@ -42,6 +42,8 @@
 	Rely on <config.h> + <unistd.h> to declare 'environ',
 	as gnulib does this if the system doesn't.
 	* callproc.c, editfns.c, process.c (environ) [!USE_CRT_DLL]:
+	Remove declaration.  MS-Windows declares it on stdlib.h which is
+	included by conf_post.h.
 	* emacs.c (environ) [DOUG_LEA_MALLOC]:
 	* vm-limit.c (environ) [ORDINARY_LINK]: Remove decl.
 	* vm-limit.c: Include <unistd.h>, for 'environ'.

src/conf_post.h

@@ -178,6 +178,9 @@ You lose; /* Emacs for DOS must be compiled with DJGPP */
 #endif
 
 #include <string.h>
+/* If you think about removing the line below, note that the
+   MS-Windows build relies on it for declaration of 'environ' needed
+   by a few source files.  */
 #include <stdlib.h>
 
 #if __GNUC__ >= 3  /* On GCC 3.0 we might get a warning.  */