Fix the build process so that it works on the Bash shell for Git on Windows

1. Made the Lua thing used be an optional variable, so it works for different Lua versions and locations

2. Made it work better with windows filesystems being weird with trailing dots.

build.sh

@@ -1,10 +1,11 @@
-#!/bin/sh
+#!/bin/bash
+LUA=${LUA:-lua}
 rm -r target/*
 mkdir target &>/dev/null
-lua luapreproc.lua module/init.lua target/init.lua
+$LUA luapreproc.lua module/init.lua target/init.lua
 echo _OSVERSION=\"PsychOS 2.0a2-$(git rev-parse --short HEAD)\" > target/version.lua
 cat target/version.lua target/init.lua > target/tinit.lua
 mv target/tinit.lua target/init.lua
 cp -r service/ lib/ cfg/ target/
-lua finddesc.lua $(find module/ -type f) $(find lib/ -type f) > apidoc.md
+$LUA finddesc.lua $(find module/ -type f) $(find lib/ -type f) > apidoc.md
 rm target/version.lua

luapreproc.lua

@@ -179,6 +179,7 @@ local env = {code = ""}
 setmetatable(env, {__index=_env})
 env:process(arg[1])
 local tmpfile = os.tmpname()
+if tmpfile:sub(#tmpfile) == "." then tmpfile = tmpfile:sub(1, #tmpfile - 1) end
 local tmpf = io.open(tmpfile, "wb")
 tmpf:write(env.code)
 tmpf:close()