Do not ignore the -arch flags MacPorts tells it to build with.
--- setup.py.orig	2017-11-11 09:35:31.000000000 -0600
+++ setup.py	2018-02-02 15:27:00.000000000 -0600
@@ -36,20 +36,6 @@
     pure = False
 
 
-if sys.platform == 'darwin' and os.path.exists('/usr/bin/xcodebuild'):
-    # XCode 4.0 dropped support for ppc architecture, which is hardcoded in
-    # distutils.sysconfig
-    import subprocess
-    p = subprocess.Popen(
-        ['/usr/bin/xcodebuild', '-version'], stdout=subprocess.PIPE,
-        stderr=subprocess.PIPE, env={})
-    out, err = p.communicate()
-    for line in out.splitlines():
-        line = line.decode("utf8")
-        # Also parse only first digit, because 3.2.1 can't be parsed nicely
-        if (line.startswith('Xcode') and
-                int(line.split()[1].split('.')[0]) >= 4):
-            os.environ['ARCHFLAGS'] = ''
 
 tests_require = ['fastimport']