add -Wmissing-declarations

This is useful for catching functions which should be static and
instances where the relevant rtcd file was not included.

BUG=webm:1584

Change-Id: Ied395847a664eedce59e8ed5180bd16d059ab0ac

diff --git a/configure b/configure
index 6204f10b6cac7158d6c0213e87e28ba6ee21a5bf..c8f1d35edf6edcedb5a205f5328c5c83367cfff0 100755 (executable)
--- a/configure
+++ b/configure
@@ -620,6 +620,8 @@ process_toolchain() {
         check_cflags -Wundef && add_cflags_only -Wundef
         check_cflags -Wframe-larger-than=52000 && \
           add_cflags_only -Wframe-larger-than=52000
+        check_cflags -Wmissing-declarations && \
+          add_cflags_only -Wmissing-declarations
         if enabled mips || [ -z "${INLINE}" ]; then
           enabled extra_warnings || check_add_cflags -Wno-unused-function
         fi