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 |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

Index: Python-2.7.2/Lib/distutils/sysconfig.py
===================================================================
--- Python-2.7.2.orig/Lib/distutils/sysconfig.py
+++ Python-2.7.2/Lib/distutils/sysconfig.py
@@ -19,13 +19,22 @@
 from distutils.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)
+
 
 # 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
@@ -74,7 +83,7 @@
 
     if os.name == "posix":
         if python_build:
-            buildir = os.path.dirname(sys.executable)
+            buildir = EXECUTABLE_DIRNAME
             if plat_specific:
                 # python.h is located in the buildir
                 inc_dir = buildir
@@ -206,7 +215,7 @@
 def get_makefile_filename():
     """Return full pathname of installed Makefile from the Python build."""
     if python_build:
-        return os.path.join(os.path.dirname(sys.executable), "Makefile")
+        return os.path.join(EXECUTABLE_DIRNAME, "Makefile")
     lib_dir = get_python_lib(plat_specific=1, standard_lib=1)
     return os.path.join(lib_dir, "config", "Makefile")
 
Index: Python-2.7.2/configure.in
===================================================================
--- Python-2.7.2.orig/configure.in
+++ Python-2.7.2/configure.in
@@ -4328,6 +4328,21 @@
 CROSS_COMPILING=$cross_compiling
 AC_SUBST(CROSS_COMPILING)
 
+#
+# Cross compiling
+#
+# special RUNSHARED
+if test "$cross_compiling" = "yes"; then
+    RUNSHARED="\
+               CROSS_COMPILING=yes \
+               _python_cross_host=${ac_cv_host} \
+               _python_sysroot=\"\$(sysroot)\" \
+               _python_srcdir=\"\$(srcdir)\" \
+               _python_prefix=\"\$(prefix)\" \
+               _python_exec_prefix=\"\$(exec_prefix)\""
+fi
+
+
 # generate output files
 AC_CONFIG_FILES(Makefile.pre Modules/Setup.config Misc/python.pc)
 AC_CONFIG_FILES([Modules/ld_so_aix], [chmod +x Modules/ld_so_aix])