Add stage 06: Lua bootstrap

The goal of stage 06 is to try parse zig synax in lua. I pulled in
lpeglable 1.2.0 and parser-gen off github to get started. All of this
needs to be cleaned up rather soon.

Lua boostraps using tcc and musl from the previous stage. Since musl
0.6.0 doesn't support dynamic linking this build of lua doesn't support
shared libraries. I couldn't easily patch musl with dlopen and friends
so instead I link statically and call deps with c api.

06/lpeglabel/examples/listIdRe2.lua

@@ -0,0 +1,71 @@
+local re = require 'relabel' 
+
+local errinfo = {
+  {"errUndef",  "undefined"},
+  {"errId",     "expecting an identifier"},
+  {"errComma",  "expecting ','"},
+}
+
+local errmsgs = {}
+local labels = {}
+
+for i, err in ipairs(errinfo) do
+  errmsgs[i] = err[2]
+  labels[err[1]] = i
+end
+
+re.setlabels(labels)
+
+local g = re.compile[[
+  S      <- Id List
+  List   <- !.  /  Comma Id List
+  Id     <- Sp {[a-z]+} / %{errId}
+  Comma  <- Sp ',' / %{errComma}
+  Sp     <- %s*
+]]
+
+local errors
+
+function recorderror (subject, pos, label)
+	local line, col = re.calcline(subject, pos)
+	table.insert(errors, { line = line, col = col, msg = errmsgs[labels[label]] })
+	return true 
+end
+
+function sync (p)
+	return '( !(' .. p .. ') .)*'
+end
+
+local grec = re.compile(
+  "S         <- %g //{errComma} ErrComma //{errId} ErrId" .. "\n" ..
+  "ErrComma  <-  ('' -> 'errComma' => recorderror) " .. sync('[a-z]+') .. "\n" ..
+	"ErrId     <-  ('' -> 'errId' => recorderror) " .. sync('","') .. "-> default" 
+	, {g = g, recorderror  = recorderror, default = "NONE"})
+
+function mymatch (g, s)
+	errors = {}
+	subject = s	
+	io.write("Input: ", s, "\n")
+	local r = { g:match(s) }
+	io.write("Captures (separated by ';'): ")
+	for k, v in pairs(r) do
+		io.write(v .. "; ")
+	end
+	io.write("\nSyntactic errors found: " .. #errors)
+	if #errors > 0 then
+		io.write("\n")
+		local out = {}
+    for i, err in ipairs(errors) do
+    	local msg = "Error at line " .. err.line .. " (col " .. err.col .. "): " .. err.msg
+      table.insert(out,  msg)
+    end
+    io.write(table.concat(out, "\n"))
+  end
+	print("\n")
+	return r
+end
+  
+mymatch(grec, "one,two")
+mymatch(grec, "one two three")
+mymatch(grec, "1,\n two, \n3,")
+mymatch(grec, "one\n two123, \nthree,")