Add path_is_within to decide if a path is within a given

directory, taking symlinks into account, and use it to
decide whether a file is within the session folder.  Should
fix #4552.


git-svn-id: svn://localhost/ardour2/branches/3.0@12468 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/pbd/wscript

@@ -139,6 +139,7 @@ def build(bld):
                 test/scalar_properties.cc
                 test/signals_test.cc
                 test/convert_test.cc
+                test/filesystem_test.cc
         '''.split()
         testobj.target       = 'run-tests'
         testobj.includes     = obj.includes + ['test', '../pbd']