[glib] gutils: fix missing include

[Philip Withnall <pwithnall src gnome org>]

commit 9ae71e32e868da10aa4c1634b5976ba00d6471ab
Author: George Barrett <bob bob131 so>
Date:   Sun Feb 18 13:28:17 2018 +1100

    gutils: fix missing include
    
    On platforms other than Win32, the g_abort symbol is #def'd to abort.
    C99 specifies that this function prototype resides in stdlib.h, but the
    required include is absent from gutils.h.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=793555

 glib/gutils.h | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/glib/gutils.h b/glib/gutils.h
index c48699aaa..52b6297dc 100644
--- a/glib/gutils.h
+++ b/glib/gutils.h
@@ -303,6 +303,7 @@ g_bit_storage_impl (gulong number)
 /* Crashes the program. */
 #if GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_50
 #ifndef G_OS_WIN32
+#  include <stdlib.h>
 #  define g_abort() abort ()
 #else
 GLIB_AVAILABLE_IN_2_50