[OE-core] [PATCH] python: ensure usage of host modules while cross compiling

[Awais Belal]

The issue is generally seen on x86 type of machines passing
-march=bdverX (X=3,4 etc) flags but in general this should
cause a problem when freshly built target modules are tried
for an import during the cross build process.
Aiding the PYTHONPATH with CROSSPYTHONPATH which contains
the native modules resolves the issue.

Signed-off-by: Awais Belal <awais_belal at mentor.com>
---
 ...e-of-native-modules-while-cross-compiling.patch | 31 ++++++++++++++++++++++
 meta/recipes-devtools/python/python_2.7.9.bb       |  1 +
 2 files changed, 32 insertions(+)
 create mode 100644 meta/recipes-devtools/python/python/0001-ensure-usage-of-native-modules-while-cross-compiling.patch

diff --git a/meta/recipes-devtools/python/python/0001-ensure-usage-of-native-modules-while-cross-compiling.patch b/meta/recipes-devtools/python/python/0001-ensure-usage-of-native-modules-while-cross-compiling.patch
new file mode 100644
index 0000000..1e87e89
--- /dev/null
+++ b/meta/recipes-devtools/python/python/0001-ensure-usage-of-native-modules-while-cross-compiling.patch
@@ -0,0 +1,31 @@
+From 4eb30173f2d254f19d5ef18fabed3bdb2e5c1182 Mon Sep 17 00:00:00 2001
+From: Awais Belal <awais_belal at mentor.com>
+Date: Fri, 30 Oct 2015 17:47:07 +0500
+Subject: [PATCH] ensure usage of native modules while cross compiling
+
+The PYTHONPATH variable augments the default search path and
+is prepended to it. We need to make sure that host modules
+are used while cross compiling otherwise an illegal instruction
+error is generated if the modules built for target are imported.
+
+Signed-off-by: Awais Belal <awais_belal at mentor.com>
+---
+ configure.ac | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/configure.ac b/configure.ac
+index 87a4f02..fa9e0dd 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -33,7 +33,7 @@ if test "$cross_compiling" = yes; then
+ 	    AC_MSG_ERROR([python$PACKAGE_VERSION interpreter not found])
+ 	fi
+         AC_MSG_RESULT($interp)
+-	PYTHON_FOR_BUILD='_PYTHON_PROJECT_BASE=$(abs_builddir) _PYTHON_HOST_PLATFORM=$(_PYTHON_HOST_PLATFORM) PYTHONPATH=$(shell test -f pybuilddir.txt && echo $(abs_builddir)/`cat pybuilddir.txt`:)$(srcdir)/Lib:$(srcdir)/Lib/plat-$(MACHDEP) '$interp
++	PYTHON_FOR_BUILD='_PYTHON_PROJECT_BASE=$(abs_builddir) _PYTHON_HOST_PLATFORM=$(_PYTHON_HOST_PLATFORM) PYTHONPATH=$(CROSSPYTHONPATH):$(shell test -f pybuilddir.txt && echo $(abs_builddir)/`cat pybuilddir.txt`:)$(srcdir)/Lib:$(srcdir)/Lib/plat-$(MACHDEP) '$interp
+     fi
+ elif test "$cross_compiling" = maybe; then
+     AC_MSG_ERROR([Cross compiling required --host=HOST-TUPLE and --build=ARCH])
+-- 
+1.9.1
+
diff --git a/meta/recipes-devtools/python/python_2.7.9.bb b/meta/recipes-devtools/python/python_2.7.9.bb
index f7e2f27..9a43cf7 100644
--- a/meta/recipes-devtools/python/python_2.7.9.bb
+++ b/meta/recipes-devtools/python/python_2.7.9.bb
@@ -26,6 +26,7 @@ SRC_URI += "\
   file://parallel-makeinst-create-bindir.patch \
   file://use_sysroot_ncurses_instead_of_host.patch \
   file://avoid_parallel_make_races_on_pgen.patch \
+  file://0001-ensure-usage-of-native-modules-while-cross-compiling.patch \
 "
 
 S = "${WORKDIR}/Python-${PV}"
-- 
1.9.1