title: GCC upgrade - GMP version causing issues
body: <p>I'm trying to update GCC on a particular linux machine I have, to a version for which there is no package available. </p>
  
  <p>I run the configure script and it complains about the version of GMP:</p>
  
  <pre><code># ../gcc/configure
  checking build system type... i686-pc-linux-gnu
  [snip]
  checking for the correct version of gmp.h... no
  configure: error: Building GCC requires GMP 4.2+, MPFR 2.4.0+ and MPC 0.8.0+.
  Try the --with-gmp, --with-mpfr and/or --with-mpc options to specify
  their locations.  Source code for these libraries 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, MPFR and/or MPC 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.
  </code></pre>
  
  <p>However, when I check gmp.h it shows:</p>
  
  <pre><code>/* Major version number is the value of __GNU_MP__ too, above and in mp.h. */
  #define __GNU_MP_VERSION 4
  #define __GNU_MP_VERSION_MINOR 2
  #define __GNU_MP_VERSION_PATCHLEVEL 1
  </code></pre>
  
  <p>and RPM reports the following:</p>
  
  <pre><code># rpm -q --qf "%{VERSION}\n" gmp
  4.2.1
  # rpm -q --qf "%{VERSION}\n" gmp-devel
  4.2.1
  </code></pre>
  
  <p>so both library and headers seem to be of a correct version to me  (confusingly, the numbering of the .so file for libgmp seems to have exactly nothing to do with the version number... that is showing as </p>
  
  <pre><code>libgmp.so -&gt; libgmp.so.3.4.1
  </code></pre>
  
  <p>Does anyone know why this might be failing? Those are the only two gmp packages installed on this machine and they are in standard /usr/include and /usr/lib locations, so they should be on the search path already.</p>