diff --git a/m4/ax_harden_compiler_flags.m4 b/m4/ax_harden_compiler_flags.m4
index a8d7743..5960a55 100644
--- a/m4/ax_harden_compiler_flags.m4
+++ b/m4/ax_harden_compiler_flags.m4
@@ -98,7 +98,6 @@
 
       AC_LANG_PUSH([C])
 
-      CFLAGS=
       ac_cv_warnings_as_errors=no
       ax_append_compile_cflags_extra=
       AS_IF([test "$ac_cv_vcs_checkout" = "yes"],[