Add a backport of http://bugs.python.org/issue16235 so we can use
python-config for cross builds.
This basically replaces the python version of python-config with a pure-shell
version that's already preprocessed when installed and doesn't depend
on the sysconfig import that usually leads to bad data/results.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>

Index: b/configure.ac
===================================================================
--- a/configure.ac
+++ b/configure.ac
@@ -885,6 +885,7 @@
 
 # Other platforms follow
 if test $enable_shared = "yes"; then
+  PY_ENABLE_SHARED=1
   AC_DEFINE(Py_ENABLE_SHARED, 1, [Defined if Python is built as a shared library.])
   case $ac_sys_system in
     BeOS*)
@@ -945,6 +946,7 @@
 
   esac
 else # shared is disabled
+  PY_ENABLE_SHARED=0
   case $ac_sys_system in
     CYGWIN*)
           BLDLIBRARY='$(LIBRARY)'
@@ -1921,6 +1923,9 @@
 AC_SUBST(BLDSHARED)
 AC_SUBST(CCSHARED)
 AC_SUBST(LINKFORSHARED)
+AC_SUBST(PY_ENABLE_SHARED)
+LIBPL="${prefix}/lib/python${VERSION}/config"
+AC_SUBST(LIBPL)
 # SO is the extension of shared libraries `(including the dot!)
 # -- usually .so, .sl on HP-UX, .dll on Cygwin
 AC_MSG_CHECKING(SO)
@@ -4588,7 +4593,7 @@
 AC_SUBST(ENSUREPIP)
 
 # generate output files
-AC_CONFIG_FILES(Makefile.pre Modules/Setup.config Misc/python.pc)
+AC_CONFIG_FILES(Makefile.pre Modules/Setup.config Misc/python.pc Misc/python-config.sh)
 AC_CONFIG_FILES([Modules/ld_so_aix], [chmod +x Modules/ld_so_aix])
 AC_OUTPUT
 
Index: b/Makefile.pre.in
===================================================================
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -166,7 +166,7 @@
 SUBDIRSTOO=	Include Lib Misc Demo
 
 # Files and directories to be distributed
-CONFIGFILES=	configure configure.ac acconfig.h pyconfig.h.in Makefile.pre.in
+CONFIGFILES=	configure configure.ac acconfig.h pyconfig.h.in Makefile.pre.in Misc/python-config.sh
 DISTFILES=	README ChangeLog $(CONFIGFILES)
 DISTDIRS=	$(SUBDIRS) $(SUBDIRSTOO) Ext-dummy
 DIST=		$(DISTFILES) $(DISTDIRS)
@@ -410,7 +410,7 @@
 
 # Default target
 all:		@DEF_MAKE_ALL_RULE@
-build_all:	$(BUILDPYTHON) oldsharedmods sharedmods gdbhooks
+build_all:	$(BUILDPYTHON) oldsharedmods sharedmods gdbhooks python-config
 
 # Compile a binary with gcc profile guided optimization.
 profile-opt:
@@ -1101,10 +1101,12 @@
 	fi; \
 	cd $(srcdir)/Lib/$(PLATDIR); $(RUNSHARED) ./regen
 
-python-config: $(srcdir)/Misc/python-config.in
+python-config: $(srcdir)/Misc/python-config.in Misc/python-config.sh
 	# Substitution happens here, as the completely-expanded BINDIR
 	# is not available in configure
-	sed -e "s,@EXENAME@,$(BINDIR)/python$(VERSION)$(EXE)," < $(srcdir)/Misc/python-config.in >python-config
+	sed -e "s,@EXENAME@,$(BINDIR)/python$(VERSION)$(EXE)," < $(srcdir)/Misc/python-config.in >python-config.py
+	# Replace makefile compat. variable references with shell script compat. ones; $(VAR) -> ${VAR}
+	sed -e 's,\$$(\([A-Za-z0-9_]*\)),\$$\{\1\},g' Misc/python-config.sh >python-config
 
 # Install the include files
 INCLDIRSTOMAKE=$(INCLUDEDIR) $(CONFINCLUDEDIR) $(INCLUDEPY) $(CONFINCLUDEPY)
@@ -1163,7 +1165,7 @@
 	$(INSTALL_SCRIPT) $(srcdir)/Modules/makesetup $(DESTDIR)$(LIBPL)/makesetup
 	$(INSTALL_SCRIPT) $(srcdir)/install-sh $(DESTDIR)$(LIBPL)/install-sh
 	$(INSTALL_SCRIPT) python-config $(DESTDIR)$(BINDIR)/python$(VERSION)-config
-	rm python-config
+	$(INSTALL_SCRIPT) python-config.py $(DESTDIR)$(LIBPL)/python-config.py
 	@if [ -s Modules/python.exp -a \
 		"`echo $(MACHDEP) | sed 's/^\(...\).*/\1/'`" = "aix" ]; then \
 		echo; echo "Installing support files for building shared extension modules on AIX:"; \
@@ -1345,6 +1347,7 @@
 		config.cache config.log pyconfig.h Modules/config.c
 	-rm -rf build platform
 	-rm -rf $(PYTHONFRAMEWORKDIR)
+	-rm -f python-config.py python-config
 
 # Make things extra clean, before making a distribution:
 # remove all generated files, even Makefile[.pre]
Index: b/Misc/python-config.sh.in
===================================================================
--- /dev/null
+++ b/Misc/python-config.sh.in
@@ -0,0 +1,102 @@
+#!/bin/sh
+
+exit_with_usage ()
+{
+	echo "Usage: $0 --prefix|--exec-prefix|--includes|--libs|--cflags|--ldflags|--extension-suffix|--help|--configdir"
+	exit $1
+}
+
+if [ "$1" = "" ] ; then
+	exit_with_usage 1
+fi
+
+# Returns the actual prefix where this script was installed to.
+installed_prefix ()
+{
+	RESULT=$(dirname $(cd $(dirname "$1") && pwd -P))
+	if which readlink >/dev/null 2>&1 ; then
+	RESULT=$(readlink -f "$RESULT")
+	fi
+	echo $RESULT
+}
+
+prefix_build="@prefix@"
+prefix_real=$(installed_prefix "$0")
+
+# Use sed to fix paths from their built to locations to their installed to locations.
+prefix=$(echo "$prefix_build" | sed "s#$prefix_build#$prefix_real#")
+exec_prefix_build="@exec_prefix@"
+exec_prefix=$(echo "$exec_prefix_build" | sed "s#$exec_prefix_build#$prefix_real#")
+includedir=$(echo "@includedir@")
+libdir=$(echo "@libdir@" | sed "s#$prefix_build#$prefix_real#")
+CFLAGS=$(echo "@CFLAGS@" | sed "s#$prefix_build#$prefix_real#")
+VERSION="@VERSION@"
+LIBM="@LIBM@"
+LIBC="@LIBC@"
+SYSLIBS="$LIBM $LIBC"
+LIBS="@LIBS@ $SYSLIBS -lpython${VERSION}"
+BASECFLAGS="@BASECFLAGS@"
+LDLIBRARY="@LDLIBRARY@"
+LINKFORSHARED="@LINKFORSHARED@"
+OPT="@OPT@"
+PY_ENABLE_SHARED="@PY_ENABLE_SHARED@"
+LDVERSION="@LDVERSION@"
+LIBDEST=${prefix}/lib/python${VERSION}
+LIBPL=$(echo "@LIBPL@" | sed "s#$prefix_build#$prefix_real#")
+SO="@SO@"
+PYTHONFRAMEWORK="@PYTHONFRAMEWORK@"
+INCDIR="-I$includedir/python${VERSION}"
+PLATINCDIR="-I$includedir/python${VERSION}"
+
+# Scan for --help or unknown argument.
+for ARG in $*
+do
+	case $ARG in
+	--help)
+		exit_with_usage 0
+	;;
+	--prefix|--exec-prefix|--includes|--libs|--cflags|--ldflags|--extension-suffix|--abiflags|--configdir)
+	;;
+	*)
+		exit_with_usage 1
+	;;
+esac
+done
+
+for ARG in "$@"
+do
+	case "$ARG" in
+	--prefix)
+		echo "$prefix"
+	;;
+	--exec-prefix)
+		echo "$exec_prefix"
+	;;
+	--includes)
+		 echo "$INCDIR $PLATINCDIR"
+	;;
+	--cflags)
+		echo "$INCDIR $PLATINCDIR $BASECFLAGS $CFLAGS $OPT"
+	;;
+	--libs)
+		echo "$LIBS"
+	;;
+	--ldflags)
+		LINKFORSHAREDUSED=
+		if [ -z "$PYTHONFRAMEWORK" ] ; then
+			LINKFORSHAREDUSED=$LINKFORSHARED
+		fi
+		LIBPLUSED=
+		if [ "$PY_ENABLE_SHARED" = "0" ] ; then
+			LIBPLUSED="-L$LIBPL"
+		fi
+		echo "$LIBPLUSED -L$libdir $LIBS $LINKFORSHAREDUSED"
+	;;
+	--extension-suffix)
+		echo "$SO"
+	;;
+	--configdir)
+		echo "$LIBPL"
+	;;
+esac
+done