[gimp] build: Add -Werror=missing-prototypes to CFLAGS where possible

[Mukund Sivaraman <muks src gnome org>]

commit 1b5a0f9d9d8c5ba29523e8446e43e040d239b4ca
Author: Mukund Sivaraman <muks banu com>
Date:   Wed Dec 7 01:38:33 2011 +0530

    build: Add -Werror=missing-prototypes to CFLAGS where possible

 configure.ac |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 4ab456f..76ea59c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -330,6 +330,12 @@ CFLAGS="$CFLAGS $extra_warnings"
 GIMP_DETECT_CFLAGS(extra_warnings, '-Wmissing-prototypes')
 CFLAGS="$CFLAGS $extra_warnings"
 
+# We really don't want anyone using code with missing prototypes, which
+# can cause random behavior. If compile breaks due to the following,
+# come to us and we will point you to a newer version which works.
+GIMP_DETECT_CFLAGS(extra_warnings, '-Werror=missing-prototypes')
+CFLAGS="$CFLAGS $extra_warnings"
+
 GIMP_DETECT_CFLAGS(extra_warnings, '-Wstrict-prototypes')
 CFLAGS="$CFLAGS $extra_warnings"