[glib] type-test: do not rely on signed integer overflow wrapping around

[Simon McVittie <smcv src gnome org>]

commit 0d28ee458f1847b3c7f3ed810b28b9a988ece40a
Author: Simon McVittie <smcv debian org>
Date:   Fri Dec 2 10:22:00 2016 +0000

    type-test: do not rely on signed integer overflow wrapping around
    
    Signed integer overflow is undefined behaviour: if a compiler
    detects signed integer overflow, it is free to compile it to absolutely
    anything.
    
    Signed-off-by: Simon McVittie <smcv debian org>
    Bug: https://bugzilla.gnome.org/show_bug.cgi?id=775510
    Reviewed-by: Colin Walters

 tests/type-test.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/tests/type-test.c b/tests/type-test.c
index e767f0f..2e91565 100644
--- a/tests/type-test.c
+++ b/tests/type-test.c
@@ -88,15 +88,15 @@ main (int   argc,
   g_assert (gsz == 0);
 
   gs = G_MAXSHORT;
-  gs++;
+  gs = (gshort) (1 + (gushort) gs);
   g_assert (gs == G_MINSHORT);
 
   gi = G_MAXINT;
-  gi++;
+  gi = (gint) (1 + (guint) gi);
   g_assert (gi == G_MININT);
 
   gl = G_MAXLONG;
-  gl++;
+  gl = (glong) (1 + (gulong) gl);
   g_assert (gl == G_MINLONG);
 
   /* Test the G_G(U)?INT(16|32|64)_FORMAT macros */