Unfortunately there are still ugly text-relocation binaries in the wild.

Unfortunately there are still ugly text-relocation binaries in the wild.
Libraries are less of a concern, because ld.so can fix them in the right
order.  So we must scan DYNAMIC for the TEXTREL marker, and not make
X LOADs immutable.  ld.so will apply changes to the text segment.  In
upcoming diff, crt0 and ld.so will then apply immutability.
ok kettenis