[Cmake] Speed optimizations, 15% to 30% faster

[Sebastien BARRE]

Hi

For these who are concerned with speed, you might give a shot at today's CVS.
We made some profiling and CMake is now 15% to 30% faster (on VTK).

Here are some numbers. In each case CMake was built Debug (we noticed that 
the Release version could be up to 2 times faster). Tcl wrapping was 
enabled for VTK, TESTING was on, as well as SHARED_LIBS and all packages 
(parallel, hybrid, etc.). Moreover, today's VTK CVS was used (all source 
files are now specified with explicit file extensions).

For each config/build type: the time elapsed while running the old 
cmake.exe, then the new one.

VTK: MSDev Studio
Elapsed time: 18 s. (time), 17.826 s. (clock)
Elapsed time: 13 s. (time), 13.169 s. (clock)

VTK: nmake
Elapsed time: 12 s. (time), 12.027 s. (clock)
Elapsed time: 10 s. (time), 10.655 s. (clock)

VTK: cygwin
Elapsed time: 21 s. (time), 22.361 s. (clock)
Elapsed time: 14 s. (time), 15.531 s. (clock)

--
Sebastien Barre