add ability to block whilst running start/stop external commands
tinysvcmdns: don't spin violently on shutdown

Linux overwrites the timeout argument with the remaining time when
select() returns, so if you don't reset it it shrinks to nothing.
Replaced with nanosleep() as per POSIX.1.
rtp/rtsp: report control port so we actually get resent packets

Detection and fix thanks to @Nachtzuster.

This still doesn't allocate the ports very cleverly at all. The port
handling code needs to be rewritten to allocate either one or three
ports, and then timing sync code can be sorted out...
fix RTSP fix

Previous commit was broken due to my stupidity.
Enable password authentication.

This was implemented a long time ago, but for some reason was never
plumbed in to the commandline options.
Typos.
Honour CC, CFLAGS and LDFLAGS in configure script.

This fixes feature detection when compiling w/o gcc (ie cross compiling).
figure out which time function to use
add delay reporting to sinks
add timing functions
synchronised playback
add support for generic sinks
remove unused functions
fix: First check if the tools configure needs are installed
fix: gcc might not be the default c compiler
fix: on a FreeBSD machine, assume OpenSSL is there

On FreeBSD, OpenSSL is always there, but no .pc file is installed,
so pkg-config does not report it
fix: only sleep if delay is positive
fix: first shutdown player, otherwise this hangs shairport on OpenBSD