[uClibc] Bug 385, add Thumb support to ARM

[John Bowler]

http://busybox.net/bugs/view.php?id=385

The remaining patches are now in the bug report - versions consistent with
the SVN head.

The problem with 'main' in static links is fixed (in both the SVN head and
0.9.28) and I have a fairly complete NSLU2 build with all the apps and
libraries apart from uclibc and libgcc build using thumb.  (The
uclibc/libgcc test comes next - that's the tricky one because if there is a
problem I have an unbootable system...)

I rearranged the dynamic linker fix so that it just fixes up STT_ARM_TFUNC
in dl-hash.c on arm/thumb - it converts it to STT_FUNC with the low bit set
(same as the change that seems to have been adopted for binutils so it
should remain compatible with newer binutils too.)

John Bowler <jbowler at acm.org>