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/stack.lua

@@ -0,0 +1,67 @@
+-- Stack Table
+-- Uses a table as stack, use <table>:push(value) and <table>:pop()
+-- Lua 5.1 compatible
+local unpack = unpack or table.unpack
+-- GLOBAL
+local Stack = {}
+
+-- Create a Table with stack functions
+function Stack:Create()
+
+  -- stack table
+  local t = {}
+  -- entry table
+  t._et = {}
+
+  -- push a value on to the stack
+  function t:push(...)
+    if ... then
+      local targs = {...}
+      -- add values
+      for _,v in ipairs(targs) do
+        table.insert(self._et, v)
+      end
+    end
+  end
+
+  -- pop a value from the stack
+  function t:pop(num)
+
+    -- get num values from stack
+    local num = num or 1
+
+    -- return table
+    local entries = {}
+
+    -- get values into entries
+    for i = 1, num do
+      -- get last entry
+      if #self._et ~= 0 then
+        table.insert(entries, self._et[#self._et])
+        -- remove last value
+        table.remove(self._et)
+      else
+        break
+      end
+    end
+    -- return unpacked entries
+    return unpack(entries)
+  end
+
+  -- get entries
+  function t:getn()
+    return #self._et
+  end
+
+  -- list values
+  function t:list()
+    for i,v in pairs(self._et) do
+      print(i, v)
+    end
+  end
+  return t
+end
+
+return {Stack=Stack}
+
+-- CHILLCODE™