Merged revisions 80320 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r80320 | matthias.klose | 2010-04-21 23:45:30 +0200 (Mi, 21 Apr 2010) | 2 lines

  setup.py: search ffi.h in include dirs, if LIBFFI_INCLUDEDIR is empty.
........

setup.py

@@ -1583,7 +1583,7 @@ class PyBuildExt(build_ext):
             inc_dirs.append('/usr/include/ffi')
 
         ffi_inc = [sysconfig.get_config_var("LIBFFI_INCLUDEDIR")]
-        if not ffi_inc:
+        if not ffi_inc or ffi_inc[0] == '':
             ffi_inc = find_file('ffi.h', [], inc_dirs)
         if ffi_inc is not None:
             ffi_h = ffi_inc[0] + '/ffi.h'