Hi all The configure scripts fails to recognise my mpfr 2.3.1 as a valid version (2.3.0+) during configuration, although I use the all the -with-mpfr switches. I see that this has been reported elsewhere as well, seemingly without receiving a proper solution. The platform in question is Solaris 10/x64. checking for correct version of gmp.h... yes checking for correct version of mpfr.h... no configure: error: Building GCC requires GMP 4.1+ and MPFR 2.3.0+. Try the --with-gmp and/or --with-mpfr options to specify their locations. Copies of these libraries' source code can be found at their respective hosting sites as well as at ftp://gcc.gnu.org/pub/gcc/infrastructure/. See also http://gcc.gnu.org/install/prerequisites.html for additional info. If you obtained GMP and/or MPFR from a vendor distribution package, make sure that you have installed both the libraries and the header files. They may be located in separate packages. Regards, Anders