free newbmp memory

Even though the program is exiting on the next line, free the
memory that was allocated. That should keep any monitoring tools
content.

win/share/tile2bmp.c

@@ -269,6 +269,7 @@ main(int argc, char *argv[])
     fwrite(newbmp, bmpsize, 1, fp);
     fclose(fp);
     Fprintf(stderr, "Total of %d tiles written to %s.\n", tilecount, bmpname);
+    free((genericptr_t) newbmp);
 
     exit(EXIT_SUCCESS);
     /*NOTREACHED*/