--- ORIG/cproj.c	Mon Nov 22 16:39:46 1993
+++ cproj.c	Thu Apr 26 18:40:10 2001
@@ -408,4 +408,4 @@
 
 /* Function to calculate UTM zone number--NOTE Longitude entered in DEGREES!!!
   ---------------------------------------------------------------------------*/
-calc_utm_zone(lon) double lon; { return((long)(((lon + 180.0) / 6.0) + 1.0)); }
+long calc_utm_zone(lon) double lon; { return((long)(((lon + 180.0) / 6.0) + 1.0)); }