webkit: disable on powerpc

webkit does not build correctly on powerpc. There is an upstream bug report
with a partial fix, but with remaining problems.
https://bugs.webkit.org/show_bug.cgi?id=113638

Until this problem is fixed, we disable webkit on powerpc.

Fixes
http://autobuild.buildroot.org/results/3ce/3ce992a663ddf1030a987bb778f8275a8e5fdef0/

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
package/linux-headers: add comment to safely ignore missing cross-compiler

For some architectures (eg. Arc, Cris, Hexagon, ia64, Parisc, Score and
Xtensa), the Linux buildsystem tries to call the cross-compiler when
installing the headers.

This is a spurious call, since a cross-compiler is not needed at all to
install the headers.

As some users have reported the issue, just add a comment in linux-headers.mk
directing the user to ignore those errors.

Reported-by: Noam Camus <noamc@ezchip.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
rt-tests: disable for uclibc mips

rt-tests is not supported by a uclibc toolchain that does not implement
_pid in struct sigevent. Currently this is all MIPS architectures
in uclibc.

Fixes:
  http://autobuild.buildroot.net/results/074/074265602bec4aba6c82d1aee389045e8ad33d4b

Signed-off-by: Ryan Barnett <rjbarnet@rockwellcollins.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
rt-tests: disable on bfin

rt-tests depends on NPTL which is not available on the bfin
architecture.

Fixes:
  http://autobuild.buildroot.net/results/ac9/ac95f73b2351d46d9a8c48caae7f6c3ea124e8bc

Signed-off-by: Ryan Barnett <rjbarnet@rockwellcollins.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Merge remote-tracking branch 'mirror/master'