Submit Change for 64bit Mac OSX builds

[Mitch]

Hello,

I'd like to summit a change to enable 64 bit builds on Mac OSX. The
change is to the GNUmakefile and allows it to work the same as it did
before. However, you can now pass an argument ARCH=x86_64 to do a 64
bit build. You can also set the OS version as well. MACOSX_VER=10.6.
The 64 bit test passed as well. I've included the difference of the
changes below.

Thanks,
Mitch


--- GNUmakefile.orig 2010-07-28 15:28:00.000000000 -0600
+++ GNUmakefile.new 2010-08-03 15:49:50.000000000 -0600
@@ -78,8 +78,12 @@
AR = libtool
ARFLAGS = -static -o
CXX = g++
-CXXFLAGS += -arch i386 -mmacosx-version-min=10.4
-LDFLAGS += -arch i386 -mmacosx-version-min=10.4
+
+ARCH ?= i386
+MACOSX_VER ?= 10.4
+
+CXXFLAGS += -arch $(ARCH) -mmacosx-version-min=$(MACOSX_VER)
+LDFLAGS += -arch $(ARCH) -mmacosx-version-min=$(MACOSX_VER)
endif

ifeq ($(UNAME),SunOS)