------- Comment #1 from jvdelisle at gcc dot gnu dot org 2008-09-01 14:00 ------- Try seeing if you need to install mpfr-devel and gmp-devel packages for your distribution. This will install the headers needed for those libraries.
Also, make sure you are building in a separate directory away from the source tree for gcc. The aforementioned are probably the most common problems I have seen. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37310