CPack: Avoid "format expects 'unsigned int'" warnings

Cast sprintf uid and gid arguments to match the type expected by their
"%-6u" format strings.

Source/CPack/cmCPackDebGenerator.cxx

@@ -771,13 +771,13 @@ static int put_arobj(CF *cfp, struct stat *sb)
     }
   if (lname > sizeof(hdr->ar_name) || strchr(name, ' '))
     (void)sprintf(ar_hb, HDR1, AR_EFMT1, (int)lname,
-                  (long int)sb->st_mtime, uid, gid, sb->st_mode,
-                  (long long)sb->st_size + lname, ARFMAG);
+                  (long int)sb->st_mtime, (unsigned)uid, (unsigned)gid,
+                  sb->st_mode, (long long)sb->st_size + lname, ARFMAG);
     else {
       lname = 0;
       (void)sprintf(ar_hb, HDR2, name,
-                    (long int)sb->st_mtime, uid, gid, sb->st_mode,
-                    (long long)sb->st_size, ARFMAG);
+                    (long int)sb->st_mtime, (unsigned)uid, (unsigned)gid,
+                    sb->st_mode, (long long)sb->st_size, ARFMAG);
       }
     off_t size = sb->st_size;