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>

 #!/bin/sh

 set -e

 printf "Running autoconf...\n"

 autoconf -Wall --force

 printf "Done. You may now run:\n    ./configure\n"