libtcc: minor adjustments
- use {B} to substitute tcc_lih_path (instead of \b)
- expand CONFIG_TCC_CRTPREFIX in CONFIG_TCC_LIBPATHS
which fixes duplicate CONFIG_SYSROOT.
- put default CONFIG_SYSROOT ("") into tcc.h
- remove hack from commit
db6fcce78f4d8ea25036dd6643e9fa83d8e52e5a
because $(tccdir)/include is already in sysincludes
- configure: error out for unrecognized options.
- win32/build-tcc.bat: put libtcc into base dir where it will
find lib/include automatically, and build libtcc_test example.