diff --git a/Lib/distutils/sysconfig.py b/Lib/distutils/sysconfig.py
index 8986dc9..d4eb368 100644
--- a/Lib/distutils/sysconfig.py
+++ b/Lib/distutils/sysconfig.py
@@ -360,11 +360,13 @@
     # On MacOSX we need to check the setting of the environment variable
     # MACOSX_DEPLOYMENT_TARGET: configure bases some choices on it so
     # it needs to be compatible.
-    # An alternative would be to force MACOSX_DEPLOYMENT_TARGET to be
-    # the same as during configure.
+    # If it isn't set we set it to the configure-time value
     if sys.platform == 'darwin' and g.has_key('CONFIGURE_MACOSX_DEPLOYMENT_TARGET'):
         cfg_target = g['CONFIGURE_MACOSX_DEPLOYMENT_TARGET']
         cur_target = os.getenv('MACOSX_DEPLOYMENT_TARGET', '')
+        if cur_target == '':
+            cur_target = cfg_target
+            os.putenv('MACOSX_DEPLOYMENT_TARGET', cfg_target)
         if cfg_target != cur_target:
             my_msg = ('$MACOSX_DEPLOYMENT_TARGET mismatch: now "%s" but "%s" during configure'
                 % (cur_target, cfg_target))
diff --git a/configure b/configure
index 1d538e4..ca9134f 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.in Revision: 1.475 .
+# From configure.in Revision: 1.477 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.59 for python 2.5.
 #
@@ -10322,11 +10322,12 @@
 	Darwin/*)
 		# Use -undefined dynamic_lookup whenever possible (10.3 and later).
 		# This allows an extension to be used in any Python
-		if test ${MACOSX_DEPLOYMENT_TARGET-10.1} '>' 10.2
+		cur_target=`sw_vers -productVersion | sed 's/\(10\.[0-9]*\).*/\1/'`
+		if test ${MACOSX_DEPLOYMENT_TARGET-${cur_target}} '>' 10.2
 		then
 			LDSHARED='$(CC) $(LDFLAGS) -bundle -undefined dynamic_lookup'
 			BLDSHARED="$LDSHARED"
-			CONFIGURE_MACOSX_DEPLOYMENT_TARGET=$MACOSX_DEPLOYMENT_TARGET
+			CONFIGURE_MACOSX_DEPLOYMENT_TARGET=${MACOSX_DEPLOYMENT_TARGET-${cur_target}}
 		else
 			LDSHARED='$(CC) $(LDFLAGS) -bundle'
 			if test "$enable_framework" ; then
diff --git a/configure.in b/configure.in
index 68720e7..9371a57 100644
--- a/configure.in
+++ b/configure.in
@@ -1324,11 +1324,12 @@
 	Darwin/*)
 		# Use -undefined dynamic_lookup whenever possible (10.3 and later).
 		# This allows an extension to be used in any Python
-		if test ${MACOSX_DEPLOYMENT_TARGET-10.1} '>' 10.2
+		cur_target=`sw_vers -productVersion | sed 's/\(10\.[[0-9]]*\).*/\1/'`
+		if test ${MACOSX_DEPLOYMENT_TARGET-${cur_target}} '>' 10.2
 		then
 			LDSHARED='$(CC) $(LDFLAGS) -bundle -undefined dynamic_lookup'
 			BLDSHARED="$LDSHARED"
-			CONFIGURE_MACOSX_DEPLOYMENT_TARGET=$MACOSX_DEPLOYMENT_TARGET
+			CONFIGURE_MACOSX_DEPLOYMENT_TARGET=${MACOSX_DEPLOYMENT_TARGET-${cur_target}}
 		else
 			LDSHARED='$(CC) $(LDFLAGS) -bundle'
 			if test "$enable_framework" ; then