--- GNUmakefile.orig	2013-05-22 13:31:13.000000000 +0200
+++ GNUmakefile	2013-05-22 13:34:05.000000000 +0200
@@ -1,4 +1,4 @@
-CXXFLAGS = -DNDEBUG -g -O2
+CXXFLAGS += -DNDEBUG -g -O2
 # -O3 fails to link on Cygwin GCC version 4.5.3
 # -fPIC is supported. Please report any breakage of -fPIC as a bug.
 # CXXFLAGS += -fPIC
@@ -36,9 +36,7 @@
 GAS219_OR_LATER = $(shell $(CXX) -xc -c /dev/null -Wa,-v -o/dev/null 2>&1 | $(EGREP) -c "GNU assembler version (2\.19|2\.[2-9]|[3-9])")
 
 ifneq ($(GCC42_OR_LATER),0)
-ifeq ($(UNAME),Darwin)
-CXXFLAGS += -arch x86_64 -arch i386
-else
+ifneq ($(UNAME),Darwin)
 CXXFLAGS += -march=native
 endif
 endif