[grits] Cast function pointers for gluTessCallback

[Andy Spencer <andys src gnome org>]

commit 109c5476a68de3a7a3ace77ecc6d30e842dd004f
Author: Andy Spencer <andy753421 gmail com>
Date:   Sun Feb 12 07:22:08 2012 +0000

    Cast function pointers for gluTessCallback
    
    The glu type does not work on Mac OSX, and an un-casted version does not
    work in Debian.. Hopefully casting it to GCallback (void-void function)
    will work both places..

 src/objects/grits-poly.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/src/objects/grits-poly.c b/src/objects/grits-poly.c
index c2c9923..357afae 100644
--- a/src/objects/grits-poly.c
+++ b/src/objects/grits-poly.c
@@ -31,9 +31,9 @@ static void grits_poly_tess(gdouble (**points)[3])
 {
 	//g_debug("GritsPoly: tess");
 	GLUtesselator *tess = gluNewTess();
-	gluTessCallback(tess, GLU_TESS_BEGIN,  glBegin);
-	gluTessCallback(tess, GLU_TESS_VERTEX, glVertex3dv);
-	gluTessCallback(tess, GLU_TESS_END,    glEnd);
+	gluTessCallback(tess, GLU_TESS_BEGIN,  G_CALLBACK(glBegin));
+	gluTessCallback(tess, GLU_TESS_VERTEX, G_CALLBACK(glVertex3dv));
+	gluTessCallback(tess, GLU_TESS_END,    G_CALLBACK(glEnd));
 	for (int pi = 0; points[pi]; pi++) {
 		gluTessBeginPolygon(tess, NULL);
 		gluTessBeginContour(tess);