diff --git a/Makefile b/Makefile
index 690fa322..a5bd524d 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,5 @@
 UNAME=$(shell uname | tr A-Z a-z | tr -d \\-[:digit:].)
+ARCH=$(shell uname -m)
 LIBPREFIX=lib
 LIBSUFFIX=a
 CXX_O=-o $@
@@ -11,7 +12,11 @@ CFLAGS_M32=-m32
 CFLAGS_M64=-m64
 BUILDTYPE=Release
 
-
+ifeq (, $(ENABLE64BIT))
+ifeq ($(ARCH), x86_64)
+ENABLE64BIT=Yes
+endif
+endif
 
 ifeq (,$(wildcard ./gtest))
 HAVE_GTEST=No