toolchain-external: fix lib64 symlinks

toolchain-external: fix lib64 symlinks

* Always link lib64 or lib32 to lib
* Only copy the architecture's lib directory to staging
* Also cleanup a couple of mkdirs (concerning some 'lib' directories).

Before this patch:

$ ls -ld host/usr/x86_64-buildroot-linux-gnu/sysroot/{,usr/}lib* target/{usr/,}lib*
drwxr-xr-x 2 samuel users 4.0K Aug 12 22:26 host/usr/x86_64-buildroot-linux-gnu/sysroot/lib/
drwxr-xr-x 2 samuel users 4.0K Aug 12 22:27 host/usr/x86_64-buildroot-linux-gnu/sysroot/lib64/
drwxr-xr-x 5 samuel users 4.0K Oct 30  2012 host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/
drwxr-xr-x 5 samuel users 4.0K Aug 12 22:27 host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib64/
drwxr-xr-x 3 samuel users 4.0K Oct 30  2012 host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/libexec/
drwxr-xr-x 2 samuel users 4.0K Aug 12 22:27 target/lib/
lrwxrwxrwx 1 samuel users    3 Aug 12 22:27 target/lib64 -> lib/
drwxr-xr-x 2 samuel users 4.0K Aug 12 22:27 target/usr/lib/
lrwxrwxrwx 1 samuel users    3 Aug 12 22:27 target/usr/lib64 -> lib/

$ find . -type l -xtype l # find broken symlinks
find: `./host/usr/x86_64-buildroot-linux-gnu/sysroot/lib64/lib': Too many levels of symbolic links
find: `./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib64/lib': Too many levels of symbolic links
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libnss_files.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libnss_nis.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libnss_compat.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libnss_nisplus.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libutil.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libthread_db.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libcidn.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libcrypt.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libm.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libnss_hesiod.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libnsl.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/librt.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libnss_db.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libanl.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libBrokenLocale.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libnss_dns.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libresolv.so
./host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/libdl.so
./target/etc/resolv.conf
./target/dev/log

After this patch:
$ ls -ld host/usr/x86_64-buildroot-linux-gnu/sysroot/{,usr/}lib* target/{usr/,}lib*
drwxr-xr-x 2 samuel users 4.0K Oct 30  2012 host/usr/x86_64-buildroot-linux-gnu/sysroot/lib/
lrwxrwxrwx 1 samuel users    5 Aug 12 22:36 host/usr/x86_64-buildroot-linux-gnu/sysroot/lib64 -> lib/
drwxr-xr-x 5 samuel users 4.0K Oct 30  2012 host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib/
lrwxrwxrwx 1 samuel users    5 Aug 12 22:36 host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib64 -> lib/
drwxr-xr-x 3 samuel users 4.0K Oct 30  2012 host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/libexec/
drwxr-xr-x 2 samuel users 4.0K Aug 12 22:36 target/lib/
lrwxrwxrwx 1 samuel users    3 Aug 12 22:36 target/lib64 -> lib/
drwxr-xr-x 2 samuel users 4.0K Aug 12 22:36 target/usr/lib/
lrwxrwxrwx 1 samuel users    3 Aug 12 22:36 target/usr/lib64 -> lib/

$ find . -type l -xtype l # find broken symlinks
./target/etc/resolv.conf
./target/dev/log

Fixes http://autobuild.buildroot.net/results/23fb6b1479d2b5906b72c9437b06ab4700ff246d/

Signed-off-by: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>