build-sys: require all defines under #if to be present

This should help to catch any errors with typos and HAVE/ENABLE mismatches.

diff --git a/meson.build b/meson.build
index 2b1da8a41b0d8b21da3903e10a61cb1a1cc9f761..da0f015b762aebd40a48b4cd02359837ad9c51c1 100644 (file)
--- a/meson.build
+++ b/meson.build
@@ -242,7 +242,7 @@ if cxx.found()
 endif
 
 foreach arg : ['-Wextra',
-               '-Wundef',
+               '-Werror=undef',
                '-Wlogical-op',
                '-Wmissing-include-dirs',
                '-Wold-style-definition',