Pedantic compiler fixes (Sven Panne)
diff --git a/progs/samples/loadppm.c b/progs/samples/loadppm.c
index bf7c8dd..5d3e3ab 100644
--- a/progs/samples/loadppm.c
+++ b/progs/samples/loadppm.c
@@ -30,7 +30,7 @@
 	exit(1);
     }
 
-    result = malloc(sizeof(PPMImage));
+    result = (PPMImage *) malloc(sizeof(PPMImage));
     if (!result)
     {
 	fprintf(stderr, "Unable to allocate memory\n");
@@ -52,7 +52,7 @@
     while (fgetc(fp) != '\n')
 	;
 
-    result->data = malloc(3 * result->sizeX * result->sizeY);
+    result->data = (GLubyte *) malloc(3 * result->sizeX * result->sizeY);
     if (!result)
     {
 	fprintf(stderr, "Unable to allocate memory\n");
diff --git a/progs/samples/nurb.c b/progs/samples/nurb.c
index f90c6ee..dc89912 100644
--- a/progs/samples/nurb.c
+++ b/progs/samples/nurb.c
@@ -216,11 +216,13 @@
     }
 }
 
+typedef void (GLAPIENTRY *callback_t)();
+
 static void Init(void)
 {
 
     theNurbs = gluNewNurbsRenderer();
-    gluNurbsCallback(theNurbs, GLU_ERROR, ErrorCallback);
+    gluNurbsCallback(theNurbs, GLU_ERROR, (callback_t) ErrorCallback);
 
     gluNurbsProperty(theNurbs, GLU_SAMPLING_TOLERANCE, 15.0);
     gluNurbsProperty(theNurbs, GLU_DISPLAY_MODE, GLU_OUTLINE_PATCH);
diff --git a/progs/samples/quad.c b/progs/samples/quad.c
index 8dec28b..5b721a4 100644
--- a/progs/samples/quad.c
+++ b/progs/samples/quad.c
@@ -102,6 +102,8 @@
     fprintf(stderr, "Quad Error: %s\n", gluErrorString(which));
 }
 
+typedef void (GLAPIENTRY *callback_t)();
+
 static void Init(void)
 {
     static GLint colorIndexes[3] = {0, 200, 255};
@@ -163,7 +165,7 @@
     }
 
     quadObj = gluNewQuadric();
-    gluQuadricCallback(quadObj, GLU_ERROR, ErrorHandler);
+    gluQuadricCallback(quadObj, GLU_ERROR, (callback_t) ErrorHandler);
 
     radius1 = 10;
     radius2 = 5;