Another interesting observation, this time about timing with Clang on Windows.

----- GLDrawDemo ( GUI MAIN CLANG SHARED BLITZ WIN32 ) (14 / 14)
main.cpp
plugin/tess2: 8 file(s) built in (0:00.90), 113 msecs / file
GLCtrl: 3 file(s) built in (0:00.58), 194 msecs / file
GLDrawDemo: 1 file(s) built in (0:00.79), 794 msecs / file
GLDraw: 20 file(s) built in (0:01.22), 61 msecs / file
plugin/glew: 1 file(s) built in (1:19.54), 79540 msecs / file <--- !!!

----- ScatterDraw_Demo ( MAIN CLANG DEBUG SHARED DEBUG_FULL BLITZ WIN32 ) (8 / 8)
ScatterDraw_Demo.cpp
ScatterDraw_Demo: 1 file(s) built in (0:02.22), 2225 msecs / file
ScatterDraw: 8 file(s) built in (1:03.92), 7991 msecs / file <--- !!!

Actually, I was using wine on Linux.