Don't error on unknown environment variables, #'substitute-in-file-name. SUPERSEDES 18270.47509.666061.606519@parhasard.net APPROVE COMMIT src/fileio.c addition: 2007-12-11 Aidan Kehoe <kehoea@parhasard.net> * fileio.c (Fsubstitute_in_file_name): On encountering non-existent environment variables or incorrect syntax for specifying environment variables (as is routine on Windows) don't error, instead pass the original strings through. tests/ChangeLog addition: 2007-12-11 Aidan Kehoe <kehoea@parhasard.net> * automated/syntax-tests.el: Check that substitute-in-file-name doesn't error when handed non-existing environment variables, passing through the specified string instead. Also check that existing environment variables are correctly substituted. Also check that double slashes in the middle of a path name are treated as re-starting the path.