diff -Nur bsnes.orig/src/Makefile bsnes/src/Makefile
--- bsnes.orig/src/Makefile	2009-06-07 03:56:29.000000000 +0200
+++ bsnes/src/Makefile	2009-06-07 23:11:08.080087129 +0200
@@ -8,7 +8,7 @@
 
 c     := $(compiler)
 cpp   := $(subst cc,++,$(compiler))
-flags := -O3 -fomit-frame-pointer -Ilib
+flags := $(CXXFLAGS) -fomit-frame-pointer -Ilib
 link  :=
 
 # profile-guided instrumentation: