feedbackd: Pass GMOBILE_USE_UNSTABLE_API to all files

No need to ack that individually

src/fbd-feedback-manager.c

@@ -16,7 +16,6 @@
 #include "fbd-feedback-theme.h"
 #include "fbd-theme-expander.h"
 
-#define GMOBILE_USE_UNSTABLE_API
 #include <gmobile.h>
 
 #include <gio/gio.h>

src/meson.build

@@ -57,6 +57,7 @@ fbd_lib = static_library(
   sources,
   include_directories : fbd_inc,
   dependencies : fbd_deps,
+  c_args: '-DGMOBILE_USE_UNSTABLE_API',
   install : false,
 )