scripts: simplify and fix the toolchain config script

The script that is installed, and which sole purpose is to dump
the .config that was used to build the toolchain, is pure insanity.

Let's make it much, much more simpler...

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.