Bindgen equivalent

[codebycruz]

This would be used with #28 and #1

-- build.lua file to create a types.lua file containing 
local bindgen = require("bindgen")

local bindings = bindgen.new()
    :withHeader("ffi.h")
    :generate()

local luaSource = bindings:asLua()

local outDir = os.getenv("LPM_OUTPUT_DIR")
local pathSep = string.sub(package.config, 1, 1)

local outFile = io.open(outDir .. pathSep .. "types.lua", "w")
outFile:write(preprocessed)
outFile:close()

Not specifically related to lpm but very useful for the project (and for Arisu / LuaJIT in general) since this would deduplicate LuaLS typings from LuaJIT C Header definitions. Plus, you'd be able to use actual C header files and get intellisense from there.

Ideally this wouldn't shell out and require a user to have a C preprocessor, but it only needs to run at build time so it doesn't matter too much.