diff --git a/Lib/_osx_support.py b/Lib/_osx_support.py
index d02b885..2cd1428 100644
--- a/Lib/_osx_support.py
+++ b/Lib/_osx_support.py
@@ -450,8 +450,16 @@
         # case and disallow installs.
         cflags = _config_vars.get(_INITPRE+'CFLAGS',
                                     _config_vars.get('CFLAGS', ''))
-        if ((macrelease + '.') >= '10.4.' and
-            '-arch' in cflags.strip()):
+        if macrelease:
+            try:
+                macrelease = tuple(int(i) for i in macrelease.split('.')[0:2])
+            except ValueError:
+                macrelease = (10, 0)
+        else:
+            # assume no universal support
+            macrelease = (10, 0)
+
+        if (macrelease >= (10, 4)) and '-arch' in cflags.strip():
             # The universal build will build fat binaries, but not on
             # systems before 10.4
 
diff --git a/Lib/distutils/tests/test_build_ext.py b/Lib/distutils/tests/test_build_ext.py
index 882eb92..d380cb6 100644
--- a/Lib/distutils/tests/test_build_ext.py
+++ b/Lib/distutils/tests/test_build_ext.py
@@ -479,8 +479,16 @@
 
         # get the deployment target that the interpreter was built with
         target = sysconfig.get_config_var('MACOSX_DEPLOYMENT_TARGET')
-        target = tuple(map(int, target.split('.')))
-        target = '%02d%01d0' % target
+        target = tuple(map(int, target.split('.')[0:2]))
+        # format the target value as defined in the Apple
+        # Availability Macros.  We can't use the macro names since
+        # at least one value we test with will not exist yet.
+        if target[1] < 10:
+            # for 10.1 through 10.9.x -> "10n0"
+            target = '%02d%01d0' % target
+        else:
+            # for 10.10 and beyond -> "10nn00"
+            target = '%02d%02d00' % target
         deptarget_ext = Extension(
             'deptarget',
             [deptarget_c],
diff --git a/Lib/test/test__osx_support.py b/Lib/test/test__osx_support.py
index 1f6ceb6..71dd00e 100644
--- a/Lib/test/test__osx_support.py
+++ b/Lib/test/test__osx_support.py
@@ -109,7 +109,9 @@
 
     def test__supports_universal_builds(self):
         import platform
-        self.assertEqual(platform.mac_ver()[0].split('.') >= ['10', '4'],
+        mac_ver_tuple = tuple(int(i) for i in
+                            platform.mac_ver()[0].split('.')[0:2])
+        self.assertEqual(mac_ver_tuple >= (10, 4),
                             _osx_support._supports_universal_builds())
 
     def test__find_appropriate_compiler(self):
diff --git a/Lib/test/test_posix.py b/Lib/test/test_posix.py
index 0048456..4d58e68 100644
--- a/Lib/test/test_posix.py
+++ b/Lib/test/test_posix.py
@@ -520,7 +520,7 @@
         if sys.platform == 'darwin':
             import sysconfig
             dt = sysconfig.get_config_var('MACOSX_DEPLOYMENT_TARGET') or '10.0'
-            if float(dt) < 10.6:
+            if tuple(int(n) for n in dt.split('.')[0:2]) < (10, 6):
                 raise unittest.SkipTest("getgroups(2) is broken prior to 10.6")
 
         # 'id -G' and 'os.getgroups()' should return the same
diff --git a/Mac/BuildScript/build-installer.py b/Mac/BuildScript/build-installer.py
index 74c2746..199b560 100755
--- a/Mac/BuildScript/build-installer.py
+++ b/Mac/BuildScript/build-installer.py
@@ -150,17 +150,19 @@
 # $MACOSX_DEPLOYMENT_TARGET -> minimum OS X level
 DEPTARGET = '10.3'
 
-target_cc_map = {
+def getDeptargetTuple():
+    return tuple([int(n) for n in DEPTARGET.split('.')[0:2]])
+
+def getTargetCompilers():
+    target_cc_map = {
         '10.3': ('gcc-4.0', 'g++-4.0'),
         '10.4': ('gcc-4.0', 'g++-4.0'),
         '10.5': ('gcc-4.2', 'g++-4.2'),
         '10.6': ('gcc-4.2', 'g++-4.2'),
-        '10.7': ('clang', 'clang++'),
-        '10.8': ('clang', 'clang++'),
-        '10.9': ('clang', 'clang++'),
-}
+    }
+    return target_cc_map.get(DEPTARGET, ('clang', 'clang++') )
 
-CC, CXX = target_cc_map[DEPTARGET]
+CC, CXX = getTargetCompilers()
 
 PYTHON_3 = getVersionTuple() >= (3, 0)
 
@@ -193,10 +195,10 @@
 def library_recipes():
     result = []
 
-    LT_10_5 = bool(DEPTARGET < '10.5')
+    LT_10_5 = bool(getDeptargetTuple() < (10, 5))
 
 #   Disable for now
-    if False:   # if (DEPTARGET > '10.5') and (getVersionTuple() >= (3, 5)):
+    if False:   # if (getDeptargetTuple() > (10, 5)) and (getVersionTuple() >= (3, 5)):
         result.extend([
           dict(
               name="Tcl 8.5.15",
@@ -304,7 +306,7 @@
           ),
         ])
 
-    if DEPTARGET < '10.5':
+    if getDeptargetTuple() < (10, 5):
         result.extend([
           dict(
               name="Bzip2 1.0.6",
@@ -458,7 +460,7 @@
             )
         )
 
-    if DEPTARGET < '10.4' and not PYTHON_3:
+    if getDeptargetTuple() < (10, 4) and not PYTHON_3:
         result.append(
             dict(
                 name="PythonSystemFixes",
@@ -679,7 +681,7 @@
     SDKPATH=os.path.abspath(SDKPATH)
     DEPSRC=os.path.abspath(DEPSRC)
 
-    CC, CXX=target_cc_map[DEPTARGET]
+    CC, CXX = getTargetCompilers()
 
     print("Settings:")
     print(" * Source directory:", SRCDIR)
diff --git a/setup.py b/setup.py
index 2b4119a..a46bf35 100644
--- a/setup.py
+++ b/setup.py
@@ -733,7 +733,9 @@
         if host_platform == 'darwin':
             os_release = int(os.uname()[2].split('.')[0])
             dep_target = sysconfig.get_config_var('MACOSX_DEPLOYMENT_TARGET')
-            if dep_target and dep_target.split('.') < ['10', '5']:
+            if (dep_target and
+                    (tuple(int(n) for n in dep_target.split('.')[0:2])
+                        < (10, 5) ) ):
                 os_release = 8
             if os_release < 9:
                 # MacOSX 10.4 has a broken readline. Don't try to build