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/parser-gen/parsers/lua-5.3.4-tests/vararg.lua

@@ -0,0 +1,142 @@
+-- $Id: vararg.lua,v 1.25 2016/11/07 13:11:28 roberto Exp $
+-- See Copyright Notice in file all.lua
+
+print('testing vararg')
+
+function f(a, ...)
+  local arg = {n = select('#', ...), ...}
+  for i=1,arg.n do assert(a[i]==arg[i]) end
+  return arg.n
+end
+
+function c12 (...)
+  assert(arg == _G.arg)    -- no local 'arg'
+  local x = {...}; x.n = #x
+  local res = (x.n==2 and x[1] == 1 and x[2] == 2)
+  if res then res = 55 end
+  return res, 2
+end
+
+function vararg (...) return {n = select('#', ...), ...} end
+
+local call = function (f, args) return f(table.unpack(args, 1, args.n)) end
+
+assert(f() == 0)
+assert(f({1,2,3}, 1, 2, 3) == 3)
+assert(f({"alo", nil, 45, f, nil}, "alo", nil, 45, f, nil) == 5)
+
+assert(c12(1,2)==55)
+a,b = assert(call(c12, {1,2}))
+assert(a == 55 and b == 2)
+a = call(c12, {1,2;n=2})
+assert(a == 55 and b == 2)
+a = call(c12, {1,2;n=1})
+assert(not a)
+assert(c12(1,2,3) == false)
+local a = vararg(call(next, {_G,nil;n=2}))
+local b,c = next(_G)
+assert(a[1] == b and a[2] == c and a.n == 2)
+a = vararg(call(call, {c12, {1,2}}))
+assert(a.n == 2 and a[1] == 55 and a[2] == 2)
+a = call(print, {'+'})
+assert(a == nil)
+
+local t = {1, 10}
+function t:f (...) local arg = {...}; return self[...]+#arg end
+assert(t:f(1,4) == 3 and t:f(2) == 11)
+print('+')
+
+lim = 20
+local i, a = 1, {}
+while i <= lim do a[i] = i+0.3; i=i+1 end
+
+function f(a, b, c, d, ...)
+  local more = {...}
+  assert(a == 1.3 and more[1] == 5.3 and
+         more[lim-4] == lim+0.3 and not more[lim-3])
+end
+
+function g(a,b,c)
+  assert(a == 1.3 and b == 2.3 and c == 3.3)
+end
+
+call(f, a)
+call(g, a)
+
+a = {}
+i = 1
+while i <= lim do a[i] = i; i=i+1 end
+assert(call(math.max, a) == lim)
+
+print("+")
+
+
+-- new-style varargs
+
+function oneless (a, ...) return ... end
+
+function f (n, a, ...)
+  local b
+  assert(arg == _G.arg)   -- no local 'arg'
+  if n == 0 then
+    local b, c, d = ...
+    return a, b, c, d, oneless(oneless(oneless(...)))
+  else
+    n, b, a = n-1, ..., a
+    assert(b == ...)
+    return f(n, a, ...)
+  end
+end
+
+a,b,c,d,e = assert(f(10,5,4,3,2,1))
+assert(a==5 and b==4 and c==3 and d==2 and e==1)
+
+a,b,c,d,e = f(4)
+assert(a==nil and b==nil and c==nil and d==nil and e==nil)
+
+
+-- varargs for main chunks
+f = load[[ return {...} ]]
+x = f(2,3)
+assert(x[1] == 2 and x[2] == 3 and x[3] == nil)
+
+
+f = load[[
+  local x = {...}
+  for i=1,select('#', ...) do assert(x[i] == select(i, ...)) end
+  assert(x[select('#', ...)+1] == nil)
+  return true
+]]
+
+assert(f("a", "b", nil, {}, assert))
+assert(f())
+
+a = {select(3, table.unpack{10,20,30,40})}
+assert(#a == 2 and a[1] == 30 and a[2] == 40)
+a = {select(1)}
+assert(next(a) == nil)
+a = {select(-1, 3, 5, 7)}
+assert(a[1] == 7 and a[2] == nil)
+a = {select(-2, 3, 5, 7)}
+assert(a[1] == 5 and a[2] == 7 and a[3] == nil)
+pcall(select, 10000)
+pcall(select, -10000)
+
+
+-- bug in 5.2.2
+
+function f(p1, p2, p3, p4, p5, p6, p7, p8, p9, p10,
+p11, p12, p13, p14, p15, p16, p17, p18, p19, p20,
+p21, p22, p23, p24, p25, p26, p27, p28, p29, p30,
+p31, p32, p33, p34, p35, p36, p37, p38, p39, p40,
+p41, p42, p43, p44, p45, p46, p48, p49, p50, ...)
+  local a1,a2,a3,a4,a5,a6,a7
+  local a8,a9,a10,a11,a12,a13,a14
+end
+
+-- assertion fail here
+f()
+
+
+print('OK')
+