scripts: always create lib32 and lib64 symlinks

Unconditionally create the lib32 -> lib/ and lib64 -> lib/ symlinks.

This is reportedly a fix to build a toolchain for a 32-bit target on
a 'pure' 64-bit host (eg. on Fedora FC12, host libs are in lib64/,
and there is no lib -> lib64 symlink, as we can see on other distors,
as Debian). As gcc only puts static host lib in lib64/ (along with
target files in subdirs), we can safely create the symlinks.

Also note that the symlinks are summarily removed at the end
of the build.

Signed-off-by: Anthony Foiani <anthony.foiani@gmail.com>
[Yann E. MORIN: fix a comment, rephrase the commit log]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 # Menu for the cross GDB

 config GDB_CROSS

     bool

     prompt "Cross-gdb"

     default y

     select GDB_GDBSERVER if ! BARE_METAL

     help

       Build and install a cross-gdb for the target, to run on host.

 if GDB_CROSS

 config GDB_CROSS_STATIC

     bool

     prompt "Build a static cross gdb"

     default n

     help

       A static cross gdb can be usefull if you debug on a machine that is

       not the one that is used to compile the toolchain.

       That way, you can share the cross-gdb without installing a toolchain

       on every machine that will be used to debug target programs.

 endif # GDB_CROSS