With a little experimentation, I found out the default search directories of GCC. Given the compile time options of, for example, PREFIX=/usr, MACHINE=i486-linux-gnu, VERSION=4.0.1, and the default GCC_EXEC_PREFIX=PREFIX/lib/gcc ... the default library search paths are... GEP/M/V GEP/M/V/../../../../M/lib/M/V GEP/M/V/../../../../M/lib ... and the default include search paths are... GEP/M/V/../../../../M/sys-include GEP/M/V/include GEP/M/V/../../../../M/include Now one can change GEP by either setting the environment variable or with the -B switch. However, what I'd really like to modify is the entire GEP/M/V portion, as well as the M in ../../../../M/{include,lib}. Can this be done? (as a little experiment, I copied the gcc binary, searched for the string i486-linux-gnu, and hacked it with an editor to be something else, and this did have the desired effect of changing the parameter M above!) Please cc me in your reply. Thanks again, Shaun