maint: exclude more files from syntax check

maint: exclude more files from syntax check

* cfg.mk (VC_LIST_ALWAYS_EXCLUDE_REGEX): Exempt
docs/api_extension/*.patch.
(exclude_file_name_regexp--sc_prohibit_always_true_header_tests)
(exclude_file_name_regexp--sc_prohibit_empty_lines_at_EOF)
(exclude_file_name_regexp--sc_prohibit_fork_wrappers)
(exclude_file_name_regexp--sc_trailing_blank): Simplify.
(exclude_file_name_regexp--sc_prohibit_gettext_noop): Delete.
(exclude_file_name_regexp--sc_prohibit_close)
(exclude_file_name_regexp--sc_prohibit_nonreentrant)
(exclude_file_name_regexp--sc_prohibit_sprintf): Tighten.