build optimizations

[Luiz Henrique de Figueiredo <lhf@...>]

Here are two points on the build process that we'd like your input on:

1. The Makefile assumes gcc. So we might as well use all gcc-specific flags
   to get a better Lua core and interpreter, for some definition of "better".
   For instance, -fomit-frame-pointer seems to generate smaller and faster
   binaries, but a Lua library compiled with -fomit-frame-pointer might not
   be debuggable. Is this really a bad thing? Or will anyone needing to debug
   the Lua library add the source code to the project and thus not rely on
   whatever pre-built Lua exists in their system? What gcc-specific flags
   should we use if we go that way?

2. The file all.c (aka one.c) allows Lua to be built as a single object file,
   and allows the compiler to generate better code and with just the Lua API
   as public symbols. We are considering building Lua in this way, so that
   liblua.a will consist of a single object file. Does anyone see a drawback
   to this?

All comments are welcome. Thanks.