cc/gcc: always build core compilers to run on the build machine

The core compilers are used to build the C library, so they
should always run on the build machine, not on the host.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 This is NOT the official version of dialog.  This version has been

 significantly modified from the original.  It is for use by the Linux

 kernel configuration script.  Please do not bother Savio Lam with 

 questions about this program.