Apple checks EUID==0 on ioctl(/dev/pf), whereas OpenBSD and FreeBSD only
check permissions on open(/dev/pf). This means that on OS X, it is not
possible to open /dev/pf, drop privileges, and send an ioctl to the file
descriptor opened earlier with EUID==0. It also means Apple broke the
Unix way of dealing with device nodes - why are there file permissions
on /dev/pf when they later enforce EUID==0 on use, thereby breaking
basic Unix mechanisms? Work around this by disallowing -u with pf
proxyspecs and by not automatically dropping to nobody on Mac OS X.
Issue: #65
Reported by: Vladimir Marteev
Add -r to force a specific SSL/TLS protocol version.
Add -R to disable one or several SSL/TLS protocol versions.
Replace WANT_SSLV2_CLIENT and WANT_SSLV2_SERVER to WITH_SSLV2.
Issue: #30
Reported by: @Apollo2342
