Don't use a redundant "const" for macros_t (which is const unsigned
char), since OpenWatcom doesn't like it, and I believe it is incorrect
per the C standard.
Instead of an array of strings, just have a character array; that
reduces the size of canned macros by up to 30%, and we only did
sequential access anyway.
Move the handling of "extra" macros (i.e. output format macros) into
the macros.pl mechanism. This allows us to change the format of the
internal macro store in the future - e.g. to a single byte store
without redundant pointers.
Also, stop using indicies into a long array when there is no good
reason to not just use different arrays.
Compress macros.c by representing macro directives with a single byte.
We can do this because we only use the ASCII character range inside
the standard macro files.
Note: we could save significant additional space by not having a
pointer array, and instead relying on the fact that we sweep
sequentially through the output array.
Introduce new preprocessor directives %depend and %pathsearch, and
make incbin a standard macro using these filenames. This lets us
remove the code that makes incbin search the path.
