openssl: build always with -Wa,--noexecstack

There is no reason to disable exec-stack only for -native builds;
binaries on the target will suffer from the same SELinux ACLs.

OpenSSL does not use executable stack so this option can be disabled
unconditionally.

Signed-off-by: Enrico Scholz <enrico.scholz@sigma-chemnitz.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
tune-xscale: Drop unneeded optimisation overrides

These hacks have been around for years and deal with old gcc issues.
They've been removed from the other use sites, we should clean up the
core tune file too.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
gcc-common: Exclude AVAILTUNES from sstate checksums

AVAILTUNES is only used as a sanity check, we don't need to
include it in the sstate checksum in this case. If included
it can cause problems when switching machines with a common
package architecture.

[YOCTO #3667]

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
mesa-common: Fix confused variable assignment/comment

Its clear this was meant to be a prepend. Also fix an out
of date comment.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
bison: Use PATH to locate m4

We can specify no path to m4 at configure time and thus avoiding
having a wrapper for that particular problem.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
image.bbclass: Drop legacy export of IMAGE_BASENAME

We used to export this in the days an external script handled the image
generation. This is no longer the case and hence we no longer need this
export.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>