scripts: do not allow commas in directories, it breaks things

The comma is used by the autotools as separator in many sed expressions,
which break if a directory contains commas.

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

 #!/bin/sh

 set -e

 printf "Running autoconf...\n"

 autoconf -Wall --force

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