Automatic C binding generation

[Ori Bernstein <ori@xxxxxxxxxxxxxx>]

I've got automatic C binding generation working enough for
demoware! I can compile and link to libsqlite3 and libc,
and interface with it using entirely too much casting.

The implementation lives here:

	https://git.eigenstate.org/ori/cbind.git/tree/

And installs a binary named cbind, which takes these
arguments:

     cbind [-h?] [-b pkg] [-I inc] [-D def] [-l lib] file.h...
         -h      print this help message
         -?      print this help message
         -b pkg  generate bindings
         -I inc  add 'inc' to your include path
         -D def  define a macro in the preprocessor e.g. -Dfoo=bar
         -l lib  link against library 'lib'

You can use it like this:

	cbind -lc -lsqlite3 \
		-I /usr/include -I/usr/local/include \
		-D__GNUCLIKE_BUILTIN_STDARG \
		-b sqlite3 \
		sqlite3.h

That command generates a rather giant module with all of the
sqlite3 types (and everything included by sqlite3.h) shoved
into one sqlite3 module.

You can call it like this:

	use "sqlite3"

	const main = {
		rc = sqlite3.sqlite3_open(("db.sqlite\0" : byte#), &db)
		if rc != 0
			std.fatal("error: {}\n", rc)
		;;
		rc = sqlite3.sqlite3_exec(db,
		    ("SELECT * FROM table;\0" : byte#),
		    (callback : sqlite3.cfunc#),
		    (0 : void#), &errmsg)
		if rc != 0
			std.fatal("error: {} ({})\n", rc, std.cstrconvp(errmsg))
			sqlite3.sqlite3_free((errmsg : void#))
		;;
		sqlite3.sqlite3_close(db)
	}

Note that the strings are explicitly null terminated, and
cast to a C string explicitly. This is one pain point that
would be nice to address.

I've updated the cbind example code to reflect the current
state of the art:

	https://git.eigenstate.org/ori/cbind-example.git

It's been tested on one platform with a small handful of
headers, so expect bugs.

Most of the code in this was written by people other than
me.  Thanks to Andrew, who wrote the C compiler that this is
based off of, and to Frank who laid the groundwork for this.

-- 
    Ori Bernstein