diff --git a/codecs/gsm/Makefile b/codecs/gsm/Makefile
index 86a61f42c9..bfa73b3c8a 100644
--- a/codecs/gsm/Makefile
+++ b/codecs/gsm/Makefile
@@ -38,9 +38,8 @@ WAV49	= -DWAV49
 ######### probably require gcc. 
 
 ifeq (, $(findstring $(OSARCH) , Darwin SunOS ))
-ifeq (, $(findstring $(PROC) , x86_64 amd64 ultrasparc sparc64 arm ppc ppc64 ia64 ))
+ifeq (, $(findstring $(PROC) , x86_64 amd64 ultrasparc sparc64 arm ppc ppc64 ia64 s390))
 ifeq (, $(findstring $(shell uname -m) , ppc ppc64 alpha armv4l ))
-ifneq (${PROC},s390)
 OPTIMIZE+=-march=$(PROC)
 endif
 endif