diff --git a/configure.in b/configure.in
index 364a3d88cd3655ab0527cdc930fcfdd396bfc340..9eaeb7e4d6f6f782b2368a5b7487a5a44f06ba99 100644
--- a/configure.in
+++ b/configure.in
@@ -779,6 +779,7 @@ if test "${gcc_wextra}" = yes; then
 	GCC_WARNINGS="${GCC_WARNINGS} -Wextra -Wno-unused-parameter"
 	GCC_WARNINGS="${GCC_WARNINGS} -Wbad-function-cast"
 	GCC_WARNINGS="${GCC_WARNINGS} -Wcast-align"
+	GCC_WARNINGS="${GCC_WARNINGS} -Wredundant-decls"
 fi
 if test "${gcc_werror}" = yes; then
 	GCC_WARNINGS="${GCC_WARNINGS} -Werror"