roland/systemtap branch

[Roland McGrath]

The roland/systemtap branch has been lingering for quite some time.
It never got merged, but there were never any coherent objections IIRC.
Related past threads I found:
	http://sourceware.org/ml/libc-alpha/2011-03/msg00001.html 
	http://sourceware.org/ml/libc-alpha/2011-02/msg00003.html 
	http://sourceware.org/ml/libc-alpha/2011-01/msg00008.html 

I believe Fedora has been using this code since Fedora 15.
(I have Fedora 16/x86_64 handy and its libc.so.6 has the notes.)

I've just rebased the branch, fixed conflicts, updated copyright years
and log entries, and adapted the x86_64 assembly bits for x32.  (The
x86_64 pthread probes written in assembly use unadorned register
names, indicating 64-bit quantities for pointer values on x32, but I
don't think it really matters.)

I've tested the build on x86_64 but not really tested using the probes
with stap or gdb.  I just eyeballed the notes with 'readelf -n' and
they all look fine.

Are there any objections to (or endorsements for) merging the branch now?

The changes still have no effect without --enable-systemtap.


Thanks,
Roland