scripts/internal: cleanup build symlinks

The symlinks are needed only during the build process.
The final gcc will still search those dirs, but will also search
the standard lib/ dirs, so we can get rid of the symlinks.

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

 reporter_name="unknown"

 reporter_url="http://iphonelinux.org/index.php/Glibc_toolchain_using_crosstool-NG"

 reporter_comment="An (experimental) toolchain targeting the Apple's iPhone."