V1 testing question

From: Vladimir Prus (ghost_at_[hidden])
Date: 2003-10-28 07:21:41

I've just made the "regression.py" test pass with msvc and borland, and I hope 
to run the entire Boost regression suite on those compilers soon. I have just 
one question now. V1 testing.jam contains:

if $(gCURRENT_TOOLSET) in $(gcc-compilers)
{
on $(target)
{
RUN_PATH = [ unique $(p) $(CYGWIN_ROOT)/$(p) $(RUN_PATH) 
$(ENV_PATH) ] ;
}
}

What is the purpose of this code?

TIA,
Volodya