To make this the default, enable this line in libtcc.c:tcc_new:
#if defined(TCC_TARGET_PE) && 0
s->leading_underscore = 1;
and then recompile tcc and also libtcc1.a
This enables native unwind semantics with longjmp on
win64 by putting an entry into the .pdata section for
each compiled fuction.
Also, the function now use a fixed stack and store arguments
into X(%rsp) rather than using push.