Various improvements for consistency
* add -Wno-packed compiler option
* add CONFIG_REGEX flag, undefined for tiny build
* disable regex commands in tiny build
* add documentation for some search commands and APIs
* reorder search tags for readability
* add isearch_yank_char
* use emacs names for:
isearch-repeat-backward, isearch-repeat-forward,
isearch-ring-advance, isearch-ring-retreat,
isearch-yank-word-or-char
* add occur alias for list-matching-lines
* add char32_to_utf8()
* restored some macros in cutils.h:
likely(x), unlikely(x), __maybe_unused, BOOL, FALSE, TRUE
* remove max(), min(), maxp(), minp(), clampp()
* add typed arithmetic functions:
min_int(), max_int(), clamp_int(), min3_int(), max3_int()
min_offset(), max_offset(), clamp_offset()
* use typed functions everywhere
* bump version to 5.4.1d
d0f7b7a904