I have upgraded to gcc 4.3.4, and noticed that on boxes that also have gcc:4.4 installed, the gcc 4.3.4 manpage is near empty. Note, its not missing, it contains a header/footer, but no information. I have checked on machines where gcc-4.3.4 is the only compiler, and their gcc 4.3.4 manpages do contain what you would expect.
This is a known issue with MAKEOPTS="", use -j1 if you want a manpage. Unrelated to which GCC is installed.
Unfortunately this bug was only fixed in >=gcc-4.4 and toolchain seems to be not interested in adding the fix to gcc-4.3. Just do what ssuominen suggested. *** This bug has been marked as a duplicate of bug 256608 ***