[glib] build: Fix -Wstrict-prototypes warning in glib-2.0.m4

[Philip Withnall <pwithnall src gnome org>]

commit 3a3af3d2d3163735eefe54b52edda16972418cd5
Author: Philip Withnall <withnall endlessm com>
Date:   Tue Oct 24 11:29:11 2017 +0100

    build: Fix -Wstrict-prototypes warning in glib-2.0.m4
    
    Signed-off-by: Philip Withnall <withnall endlessm com>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=705331

 m4macros/glib-2.0.m4 |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/m4macros/glib-2.0.m4 b/m4macros/glib-2.0.m4
index d8f03d4..23f6993 100644
--- a/m4macros/glib-2.0.m4
+++ b/m4macros/glib-2.0.m4
@@ -90,7 +90,7 @@ dnl
 #include <stdlib.h>
 
 int 
-main ()
+main (void)
 {
   unsigned int major, minor, micro;