--- m4/windowmaker.m4.orig	Tue Aug 11 20:41:14 2015
+++ m4/windowmaker.m4	Wed Feb  3 10:24:21 2016
@@ -195,7 +195,7 @@ AC_CACHE_CHECK([for secure_getenv], [wm_cv_func_secure
      wm_save_CFLAGS="$CFLAGS"
      for wm_arg in "% yes" "-D_GNU_SOURCE"; do
          AS_IF([wm_fn_lib_try_compile "stdlib.h" "const char *h;" "h = secure_getenv(\"HOME\")" dnl
-                    "`echo "$wm_arg" | sed -e 's, *%.*$,,' ` -Werror=implicit-function-declaration"],
+                    "`echo "$wm_arg" | sed -e 's, *%.*$,,' ` -Werror=implicit-function-declaration -pedantic-error"],
              [wm_cv_func_secure_getenv="`echo "$wm_arg" | sed -e 's,^.*% *,,' `"
               break])
      done