base-files: sysupgrade fail with eglibc

With eglibc, "ldd busybox" give us
    libcrypt.so.1 => /lib/libcrypt.so.1 (0x774be000)
    libm.so.6 => /lib/libm.so.6 (0x773e4000)
    libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x773c0000)
    libc.so.6 => /lib/libc.so.6 (0x77276000)
    /lib/ld.so.1 (0x774fe000)

Thus /lib/ld.so.1 is not printed by the libs fonction and isn't copied to the 'new' root before pivot root
libs() { ldd $* | awk '{print $3}'; }
https://dev.openwrt.org/browser/trunk/package/base-files/files/lib/upgrade/common.sh

With uclibc the last line of "ldd busybox" is
    ld-uClibc.so.0 => /lib/ld-uClibc.so.0 (0x77ada000)

Don't know for musl!

This patch replace https://dev.openwrt.org/changeset/19167, as glibc is gone
The other way around is to rework libs()

Please apply the fix (mine or another) on trunk and AA
Might fix https://dev.openwrt.org/ticket/12273

Signed-off-by: Etienne CHAMPETIER <etienne.champetier@free.fr>
Signed-off-by: Florian Fainelli <florian@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@36107 3c298f89-4303-0410-b956-a3cf2f4a3e73
gdb: update to 7.5-2012.12-1

Signed-off-by: Daniel Golle <dgolle@allnet.de>
Signed-off-by: Florian Fainelli <florian@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@36108 3c298f89-4303-0410-b956-a3cf2f4a3e73