* process.h (PSET): Remove.

* process.h (PSET): Remove.

Replace all uses with calls to new setter functions.
Use INLINE_HEADER_BEGIN, INLINE_HEADER_END.
(PROCESS_INLINE): New macro.
(pset_childp): New setter function.
(pset_gnutls_cred_type) [HAVE_GNUTLS]: New setter function.
* process.c (PROCESS_INLINE):
Define to EXTERN_INLINE, so that the corresponding functions
are compiled into code.
(pset_buffer, pset_command, pset_decode_coding_system)
(pset_decoding_buf, pset_encode_coding_system)
(pset_encoding_buf, pset_filter, pset_log, pset_mark, pset_name)
(pset_plist, pset_sentinel, pset_status, pset_tty_name)
(pset_type, pset_write_queue): New setter functions.