MLib — Useful Standard Library Extensions

MLib is a collection of various headers and libraries that I find useful
in a large enough number of my personal C projects.  This includes for
example: common datastructures, useful non-POSIX APIs, and 21st-century
strings.

This does not aim to be a LibC replacement, but rather a supplimentary
library.  It is a C23 library with no plans to support older standards.

The headers as of now are:
 • alloc.h — memory allocation functions
 • bitset.h — bitset implementation
 • dynarr.h — dynamic array implementation
 • errors.h — err.h-inspired diagnostics functions
 • macros.h — miscellaneous utility macros (MIN/MAX/lengthof/etc.)
 • mbio.h — multibyte file I/O
 • mbstring.h — multibyte-strings
 • optparse.h — option parsing functions
 • rune.h — inttypes.h but for runes
 • unicode/prop.h — unicode character properties
 • unicode/string.h — unicode string functions

BUILD INSTRUCTIONS:

    To build Mlib you need to have a C23 conforming C compiler.  Simply
    bootstrap the build system and run it:

        $ cc -o make make.c
        $ ./make

    To build with optimizations enabled, use the -r flag:

        $ ./make -r

DISCLAIMER:

    This library is developed for use by me (the author).  You are free
    to use this code for whatever you’d like, but do be warned that
    breaking changes may (and will) occur at any moment with no prior
    warning.  Additionally, be warned that I do not care about whether or
    not you think the API is well-designed or human-friendly.  If you
    have an issue with the code here, fix it — you are a programmer are
    you not?

Planned Features:
 • Arena Allocators            (alloc.h)
 • Missing Unicode Properties  (unicode/prop.h)
 • String Case Conversions     (unicode/string.h)
 • Unicode Normalization       (unicode/string.h)
 • Word- and Line Segmentation (unicode/string.h)