--- src/main.mk.orig	2017-01-17 09:23:50.673581733 +0100
+++ src/main.mk	2017-01-17 09:23:59.818548261 +0100
@@ -10,7 +10,7 @@
 # This file is included by primary Makefile.
 #
 
-XBCC = $(BCC) $(BCCFLAGS) $(CFLAGS)
+XBCC = $(BCC) -Os
 XTCC = $(TCC) -I. -I$(SRCDIR) -I$(OBJDIR) $(TCCFLAGS) $(CFLAGS)