Replace some typedef names by enum tags.

Also get rid of some mildly silly manual packing of enum types.

src/lib/subs/nstr.c

@@ -483,10 +483,10 @@ cond_type_mismatch(char *str)
  * messages if it is a null pointer.
  */
 int
-nstr_coerce_val(struct valstr *val, nsc_type to, char *str)
+nstr_coerce_val(struct valstr *val, enum nsc_type to, char *str)
 {
     /* FIXME get rid of promotion?  */
-    nsc_type from = nstr_promote(val->val_type);
+    enum nsc_type from = nstr_promote(val->val_type);
 
     if (from == NSC_NOTYPE)
 	return 0;

src/lib/subs/sarg.c

@@ -55,7 +55,7 @@
  *
  * or 0 for none of the above.
  */
-ns_seltype
+enum ns_seltype
 sarg_type(char *str)
 {
     int c;