After removing the default definitions of lua module tables and table
lengths (see lua_builtin.h) the symbols have been left undefined, which
results in them getting an address of NULL and a crash if there are no
user symbols and the user attempts a "require".
This patch checks the address of the table length variable and fails the
module search function of the table is not set (i.e. it behaves as if the
table was empty.)
The module searchers in the `require` package should return a string
if the module is not found, and not raise an error.
See: https://www.lua.org/manual/5.3/manual.html#pdf-package.searchers
Also make error strings contain newlines and tabs just like the original
ones.
- Remove file related functions from loader.
* All packages must be builtin.
- Remove os.tmpname.
- Interface with TLSF.
- Don't abort() when out of memory.
