canonicalize: avoid resolvepath

canonicalize: avoid resolvepath

Back when canonicalize merely provided canonicalize_file_name,
resolvepath was more efficient than implementing a complete
realpath.  But since resolvepath can't implement other modes for
canonicalize_filename_mode, using it is now just bulk on Solaris.

* m4/canonicalize.m4 (gl_FUNC_CANONICALIZE_FILENAME_MODE): Delete
unnecessary checks.
* lib/canonicalize.c (includes): Simplify.
(canonicalize_file_name): Drop resolvepath implementation.
* modules/canonicalize (Depends-on): Drop filenamecat.

Signed-off-by: Eric Blake <ebb9@byu.net>