[jhbuild] Don't assert if module doesn't support DESTDIR (GNOME bug 654592)

[Craig Keogh <cskeogh src gnome org>]

commit f5dc73514649b3d8aa647266fa82c9bdf959af20
Author: Craig Keogh <cskeogh adam com au>
Date:   Thu Jul 14 21:40:43 2011 +0930

    Don't assert if module doesn't support DESTDIR (GNOME bug 654592)

 jhbuild/modtypes/__init__.py |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)
---
diff --git a/jhbuild/modtypes/__init__.py b/jhbuild/modtypes/__init__.py
index ecec9b2..7475318 100644
--- a/jhbuild/modtypes/__init__.py
+++ b/jhbuild/modtypes/__init__.py
@@ -218,10 +218,14 @@ them into the prefix."""
 
         buildscript.packagedb.add(self.name, revision or '', destdir)
 
-        logging.info(_('Moving temporary DESTDIR %r into build prefix') % (destdir, ))
         destdir_prefix = os.path.join(destdir, stripped_prefix)
-        num_copied = self._process_install_files(destdir, destdir_prefix, buildscript.config.prefix)
-        logging.info(_('Install complete: %d files copied') % (num_copied, ))
+        if os.path.isdir(destdir_prefix):
+            logging.info(_('Moving temporary DESTDIR %r into build prefix') % (destdir, ))
+            num_copied = self._process_install_files(destdir, destdir_prefix, buildscript.config.prefix)
+            logging.info(_('Install complete: %d files copied') % (num_copied, ))
+        else:
+            logging.warning(_('Module \'%(module_name)s\' does not support '
+                            'DESTDIR') % {'module_name': self.name})
         
         # Now the destdir should have a series of empty directories:
         # $JHBUILD_PREFIX/_jhbuild/root-foo/$JHBUILD_PREFIX