Gcc-4.5.1

I have also checked the fedora package search at https://admin.fedoraproject.org/pkgdb/search/ and found that no packages for GCC are available in the repo.

With that being said we can get to the build process, gcc is in fact using the (./configure, make, make install) method for building and installing the application. But this application also have many options which can be included in the ./configure command so you will need to read all documentation in the archive you downloaded to determine your specific needs. You can refer to the slackware-current gcc build script http://slackware.mirrors.tds.net/pub/slackware/slackware-current/source/d/gcc/gcc.SlackBuild for an example of working options and steps used for compilation.

I am running CentOS 5.5 (same as RHEL 5.5) and just built gcc 4.5.1. There are a bunch of pre-requisites to build/install first and the entire process (if you run all of the tests) will take about 2 days. In any case, you will have to build from source, and I STRONGLY recommend that you use the gcc 4.4.x compiler (currently 4.4.0-6 on el5) to build it, not the default 4.1.2 compiler that is the default gcc tool chain. I tried with 4.1.2 first, and had to redo it with 4.4.

FWIW, my wife is a senior physicist working in the computer division of a major physics research lab and had to build 4.5.1 this week on Scientific Linux (a version of RHEL 5). She had a HUGE number of problems getting it all sorted out on their systems, a lot of which will be used by the LHC at CERN to analyze output from the LHC. We had an interesting time sharing our pain and suffering in this process - I am a professional consulting software engineer and work almost exclusively in Linux/Unix systems for major manufacturing corporations.