libxcb: fix path to Python modules

When building libxcb, the variable XCBPROTO_XCBPYTHONDIR must point to
the location where the Python modules needed to run the c_client.py
program are installed. The path
$(STAGING_DIR)/usr/lib/python2.6/site-packages was hardcoded. However,
it doesn't work when the version of Python installed on the host is
Python 2.5.

Therefore, add a little bit of magic to compute the host Python
version.

We also verify that Python is available on the host, as we don't build
it in Buildroot.

Fixes bug #1531.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/x11r7/libxcb/libxcb.mk

@@ -13,7 +13,8 @@ LIBXCB_AUTORECONF = NO
 LIBXCB_LIBTOOL_PATCH = NO
 LIBXCB_DEPENDENCIES = host-libxslt pthread-stubs xcb-proto xlib_libXdmcp xlib_libXau
 LIBXCB_CONF_ENV = STAGING_DIR="$(STAGING_DIR)"
-LIBXCB_MAKE_OPT = XCBPROTO_XCBINCLUDEDIR=$(STAGING_DIR)/usr/share/xcb XCBPROTO_XCBPYTHONDIR=$(STAGING_DIR)/usr/lib/python2.6/site-packages
+HOST_PYTHON_VERSION=$(shell python --version 2>&1 | sed 's/Python \(2\.[0-9]\)\..*/\1/')
+LIBXCB_MAKE_OPT = XCBPROTO_XCBINCLUDEDIR=$(STAGING_DIR)/usr/share/xcb XCBPROTO_XCBPYTHONDIR=$(STAGING_DIR)/usr/lib/python$(HOST_PYTHON_VERSION)/site-packages
 
 $(eval $(call AUTOTARGETS,package/x11r7,libxcb))
 

toolchain/dependencies/dependencies.sh

@@ -122,7 +122,7 @@ if ! $SHELL --version 2>&1 | grep -q '^GNU bash'; then
 fi;
 
 # Check that a few mandatory programs are installed
-for prog in awk bison flex msgfmt makeinfo patch gzip bzip2 perl tar wget cpio ; do
+for prog in awk bison flex msgfmt makeinfo patch gzip bzip2 perl tar wget cpio python ; do
     if ! which $prog > /dev/null ; then
 	/bin/echo -e "\nYou must install '$prog' on your build machine";
 	if test $prog = "makeinfo" ; then