From Ray Hyatt:

(dchrstr): New member d_maxpop.
(dchr): Initialize it.
(max_pop): Use it.  Use dchr[SCT_MINE].d_maxpop when called with null
argument.  RES_POP now affects mountains and plains as well.

include/sect.h

@@ -100,6 +100,7 @@ struct dchrstr {
     int d_build;		/* cost multiplier for eff */
     int d_lcms;			/* lcm's needed per point of eff */
     int d_hcms;			/* hcm's needed per point of eff */
+    int d_maxpop;		/* maximum population */
     char *d_name;		/* full name of sector type */
 };