In tex.c these variables are initialized as unsigned longs, so they should
be declared as unsigned longs. I have scanned the code base for any usage
of them in the negatives - nothing. 

Bug: https://bugs.gentoo.org/854720

Signed-off-by: Pascal Jäger <pascal.jaeger@leimstift.de>

--- a/tex.h
+++ b/tex.h
@@ -28,5 +28,6 @@ extern void disp3d(void);
 extern void set_zbuff(void);
 extern void unset_zbuff(void);
 
-extern int alfa,beta,gama,centerx,centery,centerz;
+extern unsigned long alfa,beta,gama;
+extern int centerx,centery,centerz;
 extern float zoom;