diff --git a/m4/check-cflags.m4 b/m4/check-cflags.m4
index de2e32f4..e02b8340 100644
--- a/m4/check-cflags.m4
+++ b/m4/check-cflags.m4
@@ -1,11 +1,12 @@
 dnl VKD3D_CHECK_CFLAGS(flags)
 AC_DEFUN([VKD3D_CHECK_CFLAGS],
-[AS_VAR_PUSHDEF([vkd3d_cflags], vkd3d_cv_cflags_[[$1]])dnl
-AC_CACHE_CHECK([whether the compiler supports $1], vkd3d_cflags,
-[vkd3d_cflags_saved=$CFLAGS
-CFLAGS="$CFLAGS $1 -Werror"
-AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(int argc, char **argv) { return 0; }]])],
-               [AS_VAR_SET(vkd3d_cflags, yes)], [AS_VAR_SET(vkd3d_cflags, no)])
-CFLAGS=$vkd3d_cflags_saved])
-AS_VAR_IF([vkd3d_cflags], [yes], [VKD3D_CFLAGS="$VKD3D_CFLAGS $1"])dnl
-AS_VAR_POPDEF([vkd3d_cflags])])
+  [AS_VAR_PUSHDEF([vkd3d_cflags], vkd3d_cv_cflags_[[$1]])dnl
+  AC_CACHE_CHECK([whether the compiler supports $1], vkd3d_cflags,
+  [vkd3d_cflags_saved=$CFLAGS
+  CFLAGS="$CFLAGS $1 -Werror"
+  AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(int argc, char **argv) { return 0; }]])],
+                 [AS_VAR_SET(vkd3d_cflags, yes)],
+                 [AS_VAR_SET(vkd3d_cflags, no)])
+  CFLAGS=$vkd3d_cflags_saved])
+  AS_VAR_IF([vkd3d_cflags], [yes], [VKD3D_CFLAGS="$VKD3D_CFLAGS $1"])dnl
+  AS_VAR_POPDEF([vkd3d_cflags])])