Add some cross-compilation fixes to distutils

Inspired by work done by Marc Kleine-Budde <mkl@pengutronix.de> in
PTXdist.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
 Lib/distutils/sysconfig.py |   17 +++++++++++++----
 configure.ac               |    8 +++++++-
 2 files changed, 20 insertions(+), 5 deletions(-)

Index: Python-3.3.0/Lib/distutils/sysconfig.py
===================================================================
--- Python-3.3.0.orig/Lib/distutils/sysconfig.py
+++ Python-3.3.0/Lib/distutils/sysconfig.py
@@ -16,15 +16,24 @@
 from .errors import DistutilsPlatformError
 
 # These are needed in a couple of spots, so just compute them once.
-PREFIX = os.path.normpath(sys.prefix)
-EXEC_PREFIX = os.path.normpath(sys.exec_prefix)
+EXECUTABLE_DIRNAME = os.path.dirname(os.path.realpath(sys.executable))
+if os.environ.get('CROSS_COMPILING') == 'yes':
+    _sysroot=os.environ.get('_python_sysroot')
+    PREFIX = os.path.normpath(_sysroot + os.environ.get('_python_prefix'))
+    EXEC_PREFIX = os.path.normpath(_sysroot + os.environ.get('_python_exec_prefix'))
+    if '_python_srcdir' in os.environ:
+        EXECUTABLE_DIRNAME = os.path.normpath(os.environ['_python_srcdir'])
+else:
+    PREFIX = os.path.normpath(sys.prefix)
+    EXEC_PREFIX = os.path.normpath(sys.exec_prefix)
+
 BASE_PREFIX = os.path.normpath(sys.base_prefix)
 BASE_EXEC_PREFIX = os.path.normpath(sys.base_exec_prefix)
 
 # Path to the base directory of the project. On Windows the binary may
 # live in project/PCBuild9.  If we're dealing with an x64 Windows build,
 # it'll live in project/PCbuild/amd64.
-project_base = os.path.dirname(os.path.abspath(sys.executable))
+project_base = EXECUTABLE_DIRNAME
 if os.name == "nt" and "pcbuild" in project_base[-8:].lower():
     project_base = os.path.abspath(os.path.join(project_base, os.path.pardir))
 # PC/VS7.1
@@ -98,7 +107,7 @@
             # the build directory may not be the source directory, we
             # must use "srcdir" from the makefile to find the "Include"
             # directory.
-            base = _sys_home or os.path.dirname(os.path.abspath(sys.executable))
+            base = _sys_home or EXECUTABLE_DIRNAME
             if plat_specific:
                 return base
             if _sys_home:
Index: Python-3.3.0/configure.ac
===================================================================
--- Python-3.3.0.orig/configure.ac
+++ Python-3.3.0/configure.ac
@@ -963,7 +963,13 @@
 fi
 
 if test "$cross_compiling" = yes; then
-	RUNSHARED=
+	RUNSHARED=" \
+		CROSS_COMPILING=yes \
+		_python_cross_host=${ac_cv_host} \
+		_python_sysroot=\"\$(sysroot)\" \
+		_python_srcdir=\"\$(srcdir)\" \
+		_python_prefix=\"\$(prefix)\" \
+		_python_exec_prefix=\"\$(exec_prefix)\""
 fi
 
 AC_MSG_RESULT($LDLIBRARY)