1 files changed, 65 insertions, 0 deletions
diff --git a/trunk/m4/acinclude.m4 b/trunk/m4/acinclude.m4
new file mode 100644
index 000000000..3120d8620
--- /dev/null
+++ b/trunk/m4/acinclude.m4
@@ -0,0 +1,65 @@
+dnl Turn on the additional warnings last, so -Werror doesn't affect other tests.
+
+AC_DEFUN([IDT_COMPILE_WARNINGS],[
+   if test -f $srcdir/autogen.sh; then
+	default_compile_warnings="error"
+    else
+	default_compile_warnings="no"
+    fi
+
+    AC_ARG_WITH(compile-warnings,
+                AS_HELP_STRING([--with-compile-warnings=@<:@no/yes/error@:>@],
+                               [Compiler warnings]),
+                [enable_compile_warnings="$withval"],
+                [enable_compile_warnings="$default_compile_warnings"])
+
+    warnCFLAGS=
+    if test "x$GCC" != xyes; then
+	enable_compile_warnings=no
+    fi
+
+    warning_flags=
+    realsave_CFLAGS="$CFLAGS"
+
+    case "$enable_compile_warnings" in
+    no)
+	warning_flags=
+	;;
+    yes)
+	warning_flags="-Wall -Wunused -Wmissing-prototypes -Wmissing-declarations"
+	;;
+    maximum|error)
+	warning_flags="-Wall -Wunused -Wchar-subscripts -Wmissing-declarations -Wmissing-prototypes -Wnested-externs -Wpointer-arith"
+	CFLAGS="$warning_flags $CFLAGS"
+	for option in -Wno-sign-compare -Wno-pointer-sign; do
+		SAVE_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS $option"
+		AC_MSG_CHECKING([whether gcc understands $option])
+		AC_TRY_COMPILE([], [],
+			has_option=yes,
+			has_option=no,)
+		CFLAGS="$SAVE_CFLAGS"
+		AC_MSG_RESULT($has_option)
+		if test $has_option = yes; then
+		  warning_flags="$warning_flags $option"
+		fi
+		unset has_option
+		unset SAVE_CFLAGS
+	done
+	unset option
+	if test "$enable_compile_warnings" = "error" ; then
+	    warning_flags="$warning_flags -Werror"
+	fi
+	;;
+    *)
+	AC_MSG_ERROR(Unknown argument '$enable_compile_warnings' to --enable-compile-warnings)
+	;;
+    esac
+    CFLAGS="$realsave_CFLAGS"
+    AC_MSG_CHECKING(what warning flags to pass to the C compiler)
+    AC_MSG_RESULT($warning_flags)
+
+    WARN_CFLAGS="$warning_flags"
+    AC_SUBST(WARN_CFLAGS)
+])
+