Optimization: virtual-target.actual-basename

From: Vladimir Prus (ghost_at_[hidden])
Date: 2004-12-23 03:16:44

The virtual-target.actual-basename method, which returns the real name of 
target that's passed to bjam, was computing target path and suffix for each 
target, while it can be done per-property-set.

Performance:

Femtown (reference Boost.Build)
Real: min 17:800, max 24:150, avg 20:86
User: min 16:780, max 17:520, avg 17:126

Femtown (CVS Boost.Build)
Real: min 16:940, max 18:210, avg 17:626
User: min 15:740, max 16:510, avg 16:40

TBLib (reference Boost.Build)
Real: min 10:500, max 14:320, avg 12:266
User: min 9:780, max 10:970, avg 10:323

TBLib (CVS Boost.Build)
Real: min 13:150, max 14:110, avg 13:513
User: min 9:600, max 9:880, avg 9:730