Fix previous patch, and tweak references to $0. * posix-modules: Call func_gnulib_dir before using $gnulib_dir. (func_version, func_gnulib_dir): Don't call this program gnulib-tool. (func_gnulib_dir, func_tmpdir, func_fatal_error): Avoid shell bugs with using $0 in function. * gnulib-tool (func_gnulib_dir, func_tmpdir): Likewise. (func_fatal_error): Reuse the name the user invoked us with. Signed-off-by: Eric Blake <ebb9@byu.net>