in libmpeg2/motion_comp_arm_s.S have addresses in .text, which is bad
for shared libraries.  Some environments demand that .text actually be
read-only all the time, yet MC_put_o_16_arm etc require that the addresses
be modified by the dynamic linking mechanism (dlopen, LoadLibrary, etc.)
Even in those environments which permit the dynamic linker to modify the
.text segment, the runtime cost of doing the relocation can be noticeable.

This commit rewrites the linkage, discarding the tables of addresses
in favor of tables of offsets.  All transfers are local within each individual
function, so there can be no interference by processing that occurs
after assembly, such as link-time re-ordering (even of individual functions.)

Patch by John Reiser <jreiser@bitwagon.com>