A better workaround for mips64 mimmutable problem. The problem is the

A better workaround for mips64 mimmutable problem.  The problem is the
DT_DEBUG word is inside a R LOAD that gets marked immutable, but ld.so
does a mprotect RW + adjustment + mprotect R.  DT_DEBUG is specified as
being inside the DYNAMIC range, solet's do all the immutables and then,
 on mips64 only, turn around and make DYNAMIC mutable.  That gives us
time to see if we can move DT_DEBUG or change what ld.so is doing.
discussed at length with kettenis