cpphs bug with pathnames beginning with more than one slash

[Dan Aloni]

Hi Malcolm,

If we pass pathnames starting with more than one slash to '-include',
cpphs generates invalid output. These are valid UNIX pathnames.
I've tested with version 1.20.1 on Linux.

Example:

    $ touch empty.hs
    $ cpphs --cpp -include //dev/null empty.hs
    #line 1 "test.hs"
    #line 1 "           
    #line 2 "test.hs"
    #line 1 "test.hs"

If I remove the extra '/', I get a good output:

    $ touch empty.hs
    $ cpphs --cpp -include /dev/null empty.hs
    #line 1 "test.hs"
    #line 1 "/dev/null"
    #line 2 "test.hs"
    #line 1 "test.hs"

Thanks.

--
Dan Aloni