Use (void) for no parameters, not ()

This ensures we build with -Werror=missing-parameter-type.

https://bugzilla.gnome.org/show_bug.cgi?id=687385

gio/gresource.c

@@ -38,7 +38,7 @@ struct _GResource
   GvdbTable *table;
 };
 
-static void register_lazy_static_resources ();
+static void register_lazy_static_resources (void);
 
 G_DEFINE_BOXED_TYPE (GResource, g_resource, g_resource_ref, g_resource_unref)
 

gobject/tests/threadtests.c

@@ -41,7 +41,7 @@ call_counter_init (gpointer tclass)
     }
 }
 
-static void interface_per_class_init () { call_counter_init (NULL); }
+static void interface_per_class_init (void) { call_counter_init (NULL); }
 
 /* define 3 test interfaces */
 typedef GTypeInterface MyFace0Interface;

tests/assert-msg-test.c

@@ -1,6 +1,6 @@
 #include <glib.h>
 
-int main()
+int main(int argc, char **argv)
 {
     g_assert(42 < 0);
     return 0;