linux: Don't emit a .note.ABI-tag section anymore (#26663)

We don't support pre-2.6 kernels anyway - the install docs say 2.6.28
for DRI - and apparently this confuses ld.so's sorting when multiple
libGLs are installed.  Just remove it.

Note: this is a candidate for the stable branches.

Acked-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Adam Jackson <ajax@redhat.com>
(cherry picked from commit 904b03824b4c5cc24649aa69dd1a557ddfd5dda3)
i965/vs: Fix Gen4/5 VUE map inconsistency with gl_ClipVertex

This is roughly a backport of Eric's commit 0967c362.

We avoided assigning a slot in the VUE map for gl_ClipVertex, but left
the bit set in outputs_written, producing horrible confusion further
down the pipe.

Mostly fixes rendering in source games, and probably in Freespace 2 SCP.

No Piglit regressions on Ironlake.

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>

V2: Mask out the bit, not its index. Strangely, the game still worked
with that wrong, but rendering of pretty much anything else was
completely trashed.

Reviewed-by: Paul Berry <stereotype441@gmail.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Tested-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
i965/fs: Don't try to use bogus interpolation modes pre-Gen6.

Interpolation modes other than perspective-barycentric-pixel-center (and
their associated coefficients in the WM payload) only exist in Gen6 and
later.

Unfortunately, if a varying was declared as `centroid`, we would blindly
read the nonexistant values, and so produce all manner of bad behavior
-- texture swimming, snow, etc.

Fixes rendering in Counter-Strike Source and Team Fortress 2 on
Ironlake.

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>