[libxml2] configure: Add --with-python-install-dir

[Daniel Veillard <veillard src gnome org>]

commit fcb1bb56ff21c6fe5c1dfd49b99445f6128b94e4
Author: Jonas Eriksson <jonas eriksson enea com>
Date:   Thu Mar 6 09:13:17 2014 +0100

    configure: Add --with-python-install-dir
    
    Cross-compiling the python bindings is a bit difficult today, as the
    configure script will figure out the site packages dir
    (PYTHON_SITE_PACKAGES) by either:
    
    - Generating the path to the site-package target directories using
      libdir, and see if it exists. As it is not possible to point to the
      full path of the sysroot, since that will yield the wrong install
      path, and that the directory does not neccessarily exist on the host,
      this approach will not work.
    
    - Fetch the site packages dir from the python interpreter as pointed to
      by --with-python. Since this python interpreter will point to the
      sysroot, the install dir generated will be inside the sysroot and thus
      not work.
    
    This patch approaches the problem by adding the possibility of
    explicitly stating the install dir of the python packages, leaving it up
    to the cross-compilation environment to specify it. The patch does not
    affect the default case (non-cross compilation).
    
    Signed-off-by: Jonas Eriksson <jonas eriksson enea com>

 configure.in |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/configure.in b/configure.in
index ecaa403..21ad1e7 100644
--- a/configure.in
+++ b/configure.in
@@ -148,6 +148,9 @@ AC_ARG_WITH(push,
 [  --with-push             add the PUSH parser interfaces (on)])
 AC_ARG_WITH(python,
 [  --with-python[[=DIR]]     build Python bindings if found])
+AC_ARG_WITH(python_install_dir,
+[  --with-python-install-dir=DIR
+                          install Python bindings in DIR])
 AC_ARG_WITH(reader,
 [  --with-reader           add the xmlReader parsing interface (on)])
 AC_ARG_WITH(readline,
@@ -866,6 +869,10 @@ if test "$with_python" != "no" ; then
            fi
        fi
     fi
+    if test "$with_python_install_dir" != ""
+    then
+       PYTHON_SITE_PACKAGES="$with_python_install_dir"
+    fi
     if test "$PYTHON_VERSION" != "" -a "$PYTHON_SITE_PACKAGES" = ""
     then
        if test -d $libdir/python$PYTHON_VERSION/site-packages