Index: Lib/distutils/unixccompiler.py
===================================================================
--- Lib/distutils/unixccompiler.py	(revision 80646)
+++ Lib/distutils/unixccompiler.py	(working copy)
@@ -15,7 +15,7 @@
 
 __revision__ = "$Id$"
 
-import os, sys
+import os, sys, re
 from types import StringType, NoneType
 
 from distutils import sysconfig
@@ -305,10 +305,30 @@
         dylib_f = self.library_filename(lib, lib_type='dylib')
         static_f = self.library_filename(lib, lib_type='static')
 
+        if sys.platform == 'darwin':
+            # On OSX users can specify an alternate SDK using
+            # '-isysroot', calculate the SDK root if it is specified
+            # (and use it further on)
+            cflags = sysconfig.get_config_var('CFLAGS')
+            m = re.search(r'-isysroot\s+(\S+)', cflags)
+            if m is None:
+                sysroot = '/'
+            else:
+                sysroot = m.group(1)
+
+
+
         for dir in dirs:
-            shared = os.path.join(dir, shared_f)
-            dylib = os.path.join(dir, dylib_f)
-            static = os.path.join(dir, static_f)
+            if sys.platform == 'darwin' and dir.startswith('/System/') or dir.startswith('/usr/'):
+                shared = os.path.join(sysroot, dir[1:], shared_f)
+                dylib = os.path.join(sysroot, dir[1:], dylib_f)
+                static = os.path.join(sysroot, dir[1:], static_f)
+
+            else:
+                shared = os.path.join(dir, shared_f)
+                dylib = os.path.join(dir, dylib_f)
+                static = os.path.join(dir, static_f)
+
             # We're second-guessing the linker here, with not much hard
             # data to go on: GCC seems to prefer the shared library, so I'm
             # assuming that *all* Unix C compilers do.  And of course I'm
Index: Lib/distutils/sysconfig.py
===================================================================
--- Lib/distutils/sysconfig.py	(revision 80646)
+++ Lib/distutils/sysconfig.py	(working copy)
@@ -73,10 +73,13 @@
         prefix = plat_specific and EXEC_PREFIX or PREFIX
     if os.name == "posix":
         if python_build:
-            base = os.path.dirname(os.path.abspath(sys.executable))
             if plat_specific:
-                inc_dir = base
+                inc_dir = os.path.dirname(get_makefile_filename())
             else:
+                base = os.path.join(
+                    os.path.dirname(get_makefile_filename()),
+                    get_config_var('srcdir'))
+
                 inc_dir = os.path.join(base, "Include")
                 if not os.path.exists(inc_dir):
                     inc_dir = os.path.join(os.path.dirname(base), "Include")