scripts/functions: force extract folder to archive basename

Some archives like those of the 2011.07 revisions of Linaro GCC contain a folder
name different from the archive basename, which leads to errors afterwards, e.g.
when patching. E.g.:
gcc-linaro-4.5-2011.07.tar.bz2 extracts to gcc-linaro-4.5-2011.07-0/

This patch changes CT_Extract() to force the extraction of all archives to a
folder named like the archive basename. E.g.:
gcc-linaro-4.5-2011.07.tar.bz2 now extracts to gcc-linaro-4.5-2011.07/

Signed-off-by: "Benoît THÉBAUDEAU" <benoit.thebaudeau@advansee.com>

# Bare metal config options

## select BARE_METAL

##

## help 'Bare metal' refers to those programs that run without any kernel.

## help

## help You probably want to say 'y' here if you plan to use your compiler

## help to build bootloaders. It is not yet suitable to build Linux kernels,

## help though, because the APCI stuff relies on the target C library headers

## help being available?!?!...