build-sys: upgrade shadow variable warnings to errors

diff --git a/configure.ac b/configure.ac
index b767175..878b23b 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -163,6 +163,7 @@ CC_CHECK_FLAGS_APPEND([with_cflags], [CFLAGS], [\
         -Werror=implicit-function-declaration \
         -Werror=missing-declarations \
         -Werror=return-type \
+        -Werror=shadow \
         -Wstrict-prototypes \
         -Wredundant-decls \
         -Wmissing-noreturn \