--- prboom-plus-2.6.66.old/prboom2/src/MUSIC/portmidiplayer.c
+++ prboom-plus-2.6.66/prboom2/src/MUSIC/portmidiplayer.c
@@ -273,7 +273,7 @@
   init_reset_buffer();
   reset_device();
 
-  for (int i = 0; i < 16; i++)
+  for (i = 0; i < 16; i++)
     channel_volume[i] = DEFAULT_VOLUME;
 
   return 1;