(init_process): Remove undef.

(init_process): Remove undef.
(select) [MAC_OSX]: Undefine before including sysselect.h.
(posix_pathname_to_fsspec, fsspec_to_posix_pathname) [MAC_OSX]:
Remove functions and prototypes.
(parse_value): Add parentheses around + inside shift.
(path_from_vol_dir_name): Make static.
(get_temp_dir_name): Remove unused variables `cpb' and `dir_name'.
[!MAC_OSX] (get_path_to_system_folder): Likewise.
(Fmac_get_file_creator, Fmac_get_file_type): Remove unused
variable `cCode'.
(Fmac_coerce_ae_data): Remove unused variables `fref' and `fs'.
(Fmac_get_preference): Add explicit braces to avoid ambiguous `else'.