+2012-04-18 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.
+ * INSTALL (DETAILED BUILDING AND INSTALLATION): Likewise.
+ * 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):