…of OSX specific code.
…d_config.h. this also fixes the build with stricter compilers than gcc (like clang)
sigsetjmp use setjmp. Windows is of course weird in that it seems to have sigsetjmp but not sigjmp_buf (??) so force it to use setjmp in config.w32.h.in
consistent in how we deal with the signal mask. POSIX doesn't specify what to do with the signal mask in setjmp/longjmp which has resulted in the signal mask getting saved on *BSD and not getting saved on Linux. Making the behaviour explicit via sigsetjmp/siglongjmp gives us consistency and saves expensive sigprocmask() syscalls on *BSD.
…scall on second usage.