I recently stumbled across a talk about how to make OpenGL programs a lot faster. It was held by Eskil Steenberg, a member of the OpenGL Architectural Review Board, at Blender Conference 2006.
The doc says:
"If the response file reference is just a single '@' then build looks for a file called 'build.brf'"
But build 2.09 (1197) looks for the file @build.brf if I call it with ...