Put former NATIVE_DEFINES into config.h. Such tcc can be run
and tested directly from source more easily, like for example:
tcc -run tcc.c -B. -run test.c
Also:
- tccelf.c: cleanup
- tccpp.c: avoid stupid clang warning
- configure: reduce -Wno- switches
- tcc.h: inline wait/post_sem()
- tccpe.c: simplify import (assume STT_NOTYPE is function)