Kill -arch from OSX Makefile

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/Makefile.mac b/Makefile.mac
index 952364a..25c7fde 100644
--- a/Makefile.mac
+++ b/Makefile.mac
@@ -1,7 +1,7 @@
 CC	= gcc
 DEBUGFLAGS = -D_FORTIFY_SOURCE=2 -DFIO_INC_DEBUG
 OPTFLAGS= -O2 -g $(EXTFLAGS)
-CFLAGS	= -Wwrite-strings -Wall -D_GNU_SOURCE -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 $(OPTFLAGS) $(DEBUGFLAGS) -rdynamic -arch i386 -arch x86_64 -arch ppc
+CFLAGS	= -Wwrite-strings -Wall -D_GNU_SOURCE -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 $(OPTFLAGS) $(DEBUGFLAGS) -rdynamic
 PROGS	= fio
 SCRIPTS = fio_generate_plots
 OBJS = gettime.o fio.o ioengines.o init.o stat.o log.o time.o filesetup.o \