WL#1007: Check GCC profiling based branch prediction

GCC 3 has an option -fbranch-probabilities which allows to use jump usage
statistics for jump optimization. This could possibly give good bit of performance.

We need to check this and advice Lenz how to add this to distribution build
process if it gives any benefit.

Other new optimization options which we could possibly benefit shall also be
scanned.

References
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Profile guided optimization with gcc by Domas Mituzas
http://planet.mysql.com/entry/?id=20401