diff -r 693e1f01d09a configure
--- a/configure	Fri Feb 01 10:50:46 2013 +0000
+++ b/configure	Sun Feb 03 23:50:11 2013 +0200
@@ -703,6 +703,7 @@
 EXPORT_MACOSX_DEPLOYMENT_TARGET
 CONFIGURE_MACOSX_DEPLOYMENT_TARGET
 SGI_ABI
+SLPFLAGS
 _PYTHON_HOST_PLATFORM
 MACHDEP
 FRAMEWORKINSTALLAPPSPREFIX
@@ -716,6 +717,7 @@
 PYTHONFRAMEWORKDIR
 PYTHONFRAMEWORKIDENTIFIER
 PYTHONFRAMEWORK
+STACKLESS_FRHACK
 LIPO_32BIT_FLAGS
 ARCH_RUN_32BIT
 UNIVERSALSDK
@@ -780,6 +782,7 @@
 enable_universalsdk
 with_universal_archs
 with_framework_name
+enable_stacklessfewerregisters
 enable_framework
 with_gcc
 with_cxx_main
@@ -1432,6 +1435,8 @@
   --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
   --enable-universalsdk[=SDKDIR]
                           Build fat binary against Mac OS X SDK
+  --enable-stacklessfewerregisters
+                          save fewer registers building c-stack switching
   --enable-framework[=INSTALLDIR]
                           Build (MacOSX|Darwin) framework
   --enable-shared         disable/enable building shared python library
@@ -3121,6 +3126,16 @@
 
 fi
 
+
+# Check whether --enable-stacklessfewerregisters was given.
+if test "${enable_stacklessfewerregisters+set}" = set; then :
+  enableval=$enable_stacklessfewerregisters; STACKLESS_FRHACK=1
+else
+   STACKLESS_FRHACK=0
+fi
+
+
+
 # Check whether --enable-framework was given.
 if test "${enable_framework+set}" = set; then :
   enableval=$enable_framework;
@@ -3316,6 +3331,17 @@
 	_PYTHON_HOST_PLATFORM="$MACHDEP${_host_cpu:+-$_host_cpu}"
 fi
 
+# Stackless flags for compiling the hard switching code
+case $MACHDEP in
+	darwin)
+		SLPFLAGS="-fomit-frame-pointer -O2"
+		;;
+	*)
+		SLPFLAGS="-fno-omit-frame-pointer -O2"
+		;;
+esac
+
+
 # Some systems cannot stand _XOPEN_SOURCE being defined at all; they
 # disable features if it is defined, without any means to access these
 # features as extensions. For these systems, we skip the definition of
@@ -6381,6 +6407,7 @@
                 ;;
     esac
 
+    BASECFLAGS="${BASECFLAGS} -DSTACKLESS_FRHACK=${STACKLESS_FRHACK}"
     case $ac_sys_system in
 	SCO_SV*)
 	    BASECFLAGS="$BASECFLAGS -m486 -DSCO5"
@@ -14996,7 +15023,7 @@
 done
 
 
-SRCDIRS="Parser Grammar Objects Python Modules Mac"
+SRCDIRS="Parser Grammar Objects Python Modules Mac Stackless Stackless/core Stackless/module Stackless/pickling"
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for build directories" >&5
 $as_echo_n "checking for build directories... " >&6; }
 for dir in $SRCDIRS; do
@@ -15137,6 +15164,13 @@
     esac
 fi
 
+SLPFLAGS="-fno-omit-frame-pointer -O2"
+case $MACHDEP in
+darwin) SLPFLAGS="-fomit-frame-pointer -O2";;
+'') SLPFLAGS="-fno-omit-frame-pointer -O2";;
+esac
+
+
 # generate output files
 ac_config_files="$ac_config_files Makefile.pre Modules/Setup.config Misc/python.pc"