Display error messages when parsing a Lua statement fails. Previously,
executing a syntactically invalid statement like ")foo" or "bar;" would
silently fail.
* script/lua/grub_main.c (handle_lua_error): New function.
(grub_lua_parse_line): Improved reporting of Lua parser and execution
errors.
* script/lua/grub_lib.c (grub_lua_getenv): Make name and value
const to avoid a warning.
(grub_lua_setenv): Likewise.
* script/lua/grub_main.c (grub_lua_parse_line): Use size_t for
lmsg to fix a warning.
