tcc_define_symbol(): now only for -D on command line
include/tccdefs.h: converted to strings and compiled into
the tcc executable. Can be disabled with
./configure --config-predefs=no
In this case include/tccdefs.h is loaded at runtime. This is
default for other build-methods (build-tcc.bat) also (to avoid
some complexity).
Also:
- lib/Makefile: fix typo
- tcc.h : avoid _strto(u)i64 (for TCC on WIN98/2K)
- tccpp.h:cstr_printf() : workaround incompatible vsnprintf's
(generally faster too)