[RFA] Turn on -Werror by default

[Mark Kettenis <mark.kettenis@xs4all.nl>]

A while ago, we basically agreed that this would be a good thing to do
after the release.  I tried to steal the code form BFD, but that
didn't really fit in very well in our configure.ac.  Anyway, this adds
--enable-werror, defaulting to "yes", so to turn it off you'll
probably want to use --disable-werror.  This is similar to what BFD
does, so you can easily disable -Werror for the whole tree.  To
disable -Werror for GDB only, you can use
--enable-gdb-build-warnings=,-Wno-error.

ok?

Mark


Index: configure.ac
===================================================================
RCS file: /cvs/src/src/gdb/configure.ac,v
retrieving revision 1.25
diff -u -p -r1.25 configure.ac
--- configure.ac	17 Dec 2005 22:33:59 -0000	1.25
+++ configure.ac	8 Jan 2006 17:54:43 -0000
@@ -1109,6 +1109,24 @@ AC_ARG_WITH(sysroot,
 AC_SUBST(TARGET_SYSTEM_ROOT)
 AC_SUBST(TARGET_SYSTEM_ROOT_DEFINE)
 
+AC_ARG_ENABLE(werror,
+  [  --enable-werror    treat compile warnings as errors],
+  [case "${enableval}" in
+     yes | y) ERROR_ON_WARNING="yes" ;;
+     no | n)  ERROR_ON_WARNING="no" ;;
+     *) AC_MSG_ERROR(bad value ${enableval} for --enable-werror) ;;
+   esac])
+
+# Enable -Werror by default when using gcc
+if test "${GCC}" = yes -a -z "${ERROR_ON_WARNING}" ; then
+    ERROR_ON_WARNING=yes
+fi
+
+WERROR_CFLAGS=""
+if test "${ERROR_ON_WARNING}" = yes ; then
+    WERROR_CFLAGS="-Werror"
+fi
+
 # NOTE: Don't add -Wall or -Wunused, they both include
 # -Wunused-parameter which reports bogus warnings.
 # NOTE: If you add to this list, remember to update
@@ -1164,7 +1182,6 @@ if test x"$silent" != x"yes" && test x"$
   echo "Setting GDB specific compiler warning flags = $build_warnings" 6>&1
 fi])dnl
 WARN_CFLAGS=""
-WERROR_CFLAGS=""
 if test "x${build_warnings}" != x -a "x$GCC" = xyes
 then
     AC_MSG_CHECKING(compiler warning flags)