diff --git a/codecs/gsm/Makefile b/codecs/gsm/Makefile
index 1153fee5d6..f8a4c477ad 100644
--- a/codecs/gsm/Makefile
+++ b/codecs/gsm/Makefile
@@ -37,7 +37,7 @@ WAV49	= -DWAV49
 ######### ppro's, etc, as well as the AMD K6 and K7.  The compile will
 ######### probably require gcc. 
 
-ifeq (,$(findstring $(OSARCH),Darwin SunOS))
+ifeq (,$(findstring $(shell uname -s),Darwin SunOS))
   ifeq (,$(strip $(findstring $(PROC) ,"x86_64 amd64 ultrasparc sparc64 arm armv5b armeb ppc powerpc ppc64 ia64 s390 bfin mipsel mips ")))
     ifeq (,$(strip $(findstring $(shell uname -m) ,"ppc ppc64 alpha armv4l s390 ")))
       OPTIMIZE+=-march=$(PROC)