- (djm) [configure.ac] Fix detection of capsicum sandbox on FreeBSD
 - (djm) [configure.ac] Do not attempt to use capsicum sandbox unless
   sys/capability.h exists and cap_rights_limit is in libc. Fixes
   build on FreeBSD9x which provides the header but not the libc
   support.

 - (djm) [configure.ac] autoconf sets finds to 'yes' not '1', so test
   against the correct thing.