We added "--enable-optimize" to configure in 1.8 but it does hardly more
than "--disable-debug" would.  So, with this patch, we will actually enable
very expensive optimizations (when available) in optimized mode.

I measured a 5% performance gain in 'svnadmin verify'. YMMV.

* configure.ac
  (enable_optimization): go for -O3 instead of -O2; enable link time
  optimization and whole program optimization

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1445063 13f79535-47bb-0310-9956-ffa450edef68