[klibc] Fix header installation from out-of-tree build

Origin: https://git.kernel.org/pub/scm/libs/klibc/klibc.git/commit?id=8d6ee65cc8bd75bba8f51589c667ff7c5fd9b3b5
Bug-Debian: https://bugs.debian.org/1004465

In an out-of-tree build we currently only install the kernel UAPI
headers and the generated <klibc/havesyscall.h>.  Add an extra
command to copy headers from the source tree in an out-of-tree
build.

References: https://bugs.debian.org/1004465
Reported-by: Thorsten Glaser <tg@mirbsd.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Gbp-Pq: Name 0001-klibc-Fix-header-installation-from-out-of-tree-build.patch

[klibc] ia64: Fix out-of-tree build

Origin: https://git.kernel.org/pub/scm/libs/klibc/klibc.git/commit/?id=2114e20cf16bbfb45a94aaf978d62d08d8968414

The linker script is currently not found in an out-of-tree build.
The filename needs to start with $(srctree) to make this work.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Gbp-Pq: Name 0001-klibc-ia64-Fix-out-of-tree-build.patch

[klibc] Kbuild: Include provided KCFLAGS in KLIBCCFLAGS

If KCFLAGS is provided through the environment or make variables, use
it in addition to all the options we need.

Gbp-Pq: Name klibc-kbuild-include-provided-kcflags-in-klibccflags.patch

klibc (2.0.10-4) unstable; urgency=medium

  * d/control, d/rules: Remove ccache from $PATH instead of Build-Conflicting
  * d/salsa-ci.yml: Add CI configuration for salsa.debian.org
  * d/tests: Add klcc smoke test
  * Fix header installation from out-of-tree build (Closes: #1004465)

[dgit import unpatched klibc 2.0.10-4]

Import klibc_2.0.10-4.debian.tar.xz

[dgit import tarball klibc 2.0.10-4 klibc_2.0.10-4.debian.tar.xz]

Import klibc_2.0.10.orig.tar.xz

[dgit import orig klibc_2.0.10.orig.tar.xz]