Always set CONFIGURE_MACOSX_DEPLOYMENT_TARGET otherwise it may be set
to an empty value and distutils will get confused lateron.
diff --git a/configure b/configure
index ca9134f..edb0b16 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.in Revision: 1.477 .
+# From configure.in Revision: 1.478 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.59 for python 2.5.
 #
@@ -10323,11 +10323,11 @@
 		# Use -undefined dynamic_lookup whenever possible (10.3 and later).
 		# This allows an extension to be used in any Python
 		cur_target=`sw_vers -productVersion | sed 's/\(10\.[0-9]*\).*/\1/'`
+		CONFIGURE_MACOSX_DEPLOYMENT_TARGET=${MACOSX_DEPLOYMENT_TARGET-${cur_target}}
 		if test ${MACOSX_DEPLOYMENT_TARGET-${cur_target}} '>' 10.2
 		then
 			LDSHARED='$(CC) $(LDFLAGS) -bundle -undefined dynamic_lookup'
 			BLDSHARED="$LDSHARED"
-			CONFIGURE_MACOSX_DEPLOYMENT_TARGET=${MACOSX_DEPLOYMENT_TARGET-${cur_target}}
 		else
 			LDSHARED='$(CC) $(LDFLAGS) -bundle'
 			if test "$enable_framework" ; then