cc/gcc: gcc-4.4 does not use MPC

As reported by Johannes Stezenbach, see thread at:
http://sourceware.org/ml/crossgcc/2010-07/msg00017.html

 # Compute IA-64-specific values

 CT_DoArchTupleValues() {

     # The architecture part of the tuple:

     CT_TARGET_ARCH="${CT_ARCH}"

 }