... while POSIX threads are available.
Various features don't even compile when not using threads.
if test $have_pthread = yes; then
AC_MSG_WARN([pthreads seem to be available but you are using --disable-pthread.])
AC_MSG_WARN([This is almost always a mistake and can render Privoxy unacceptable slow.])
+ AC_MSG_WARN([Also various Privoxy features only work when using threads and won't even compile without them.])
fi
have_pthread=no
fi])