1, #include "stdio.h" of 'musl libc' ok,

1, #include "stdio.h" of 'musl libc' ok,
2, #if expr only has const integer & identity,
3, support '__builtin_va_list, __builtin_va_start(), __builtin_va_arg(), __builtin_va_end()',
4, support -D to define macro in cmd line,
5, fix: macro in *.c defined before can't be found in *.h files by #include,
6, add option -p to parse the source code only, not compile or make 3ac code,
7, close some logs.