g2: fix gpointer cast complaints

Type: fix

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: Iadd6a4dd928002e764fc52343c14403620279aa7
diff --git a/src/tools/g2/pointsel.c b/src/tools/g2/pointsel.c
index 5982237..fae9336 100644
--- a/src/tools/g2/pointsel.c
+++ b/src/tools/g2/pointsel.c
@@ -169,7 +169,7 @@
 static void button_click_callback(GtkButton *item, gpointer data)
 {
     int i;
-    enum button_click click = (enum button_click)data;
+    enum button_click click = (enum button_click) (long int) data;
 
     switch (click) {
     case ALL_BUTTON: