for fedora you can try: yum list \*gcc*
i found arm-gp2x-linux-gcc.x86_64 which doesn't look right for bb
for other distros, similar commands can be tried
for gentoo or debian
i'm still trying to find/make arm gcc 4.5 either cross or native.
(cross would be nice for distcc, thanks to Henrik Nordström for that pointer)
i can't get bitbake to cooperate so i'm looking at rpmbuild now...