how to check what compiler is running

From: brock_peabody (bpyama_at_[hidden])
Date: 2003-10-18 14:29:39

I want to set a local variable based on what compiler is running:

local exe_destination ;

if msvc_is_running {

exe_destination = "c:\\msvc_exes";
}
else if [ os.name ] = NT { #cygwin

exe_destination = "c:\\cygwin\\cygwin_exes" ;
}
else {

exe_destination = "/home/peabody/linux_exes";
}

I gleaned the "if [ os.name ] = NT" from tools/msvc.jam, but I can't 
figure out how to check to see if msvc itself is running.

Thanks!