[PATCH v3 2/2] oeqa/sdk: build the kernel's host tools with a host pkg-config

[Trevor Woerner <twoerner@gmail.com>]

The SDK environment sets PKG_CONFIG_SYSROOT_DIR, PKG_CONFIG_PATH and
PKG_CONFIG_LIBDIR so that pkg-config answers for the target. That is
right for everything built to run there and wrong for a program built to
run on the SDK host.

The kernel build compiles host tools of its own, and objtool queries
pkg-config for the libelf include path. The answer is the target's
include directory, so a host tool is compiled against the target's C
library headers, and the build stops on warnings that
-Wno-system-headers would otherwise have covered:

  usr/include/sys/cdefs.h:486: error: "__attribute_const__" redefined

Pass pkg-config-native on the make command line when the test builds an
external module. The SDK already ships that wrapper, it already answers
for the build machine, and kernel.bbclass already gives its own host
tools the same one, so the two agree rather than each undoing the
environment in its own way. It has to be a command line assignment: the
kernel assigns HOSTPKG_CONFIG with '=', so an exported value is ignored.

Fixes [YOCTO #16239].

AI-Generated: codex/claude-opus 5 (xhigh)
Signed-off-by: Trevor Woerner <twoerner@gmail.com>
---
changes in v3:
- use pkg-config-native, the wrapper kernel.bbclass already gives its
  own host tools, instead of spelling out an env -u invocation of the
  SDK's pkg-config

changes in v2:
- drop the HOSTPKG_CONFIG export from the SDK environment script. It
  only ever took effect against a proposed kernel change that has since
  been abandoned, so no kernel honours it and it was dead weight. The
  make command line assignment, which is what makes the test work, is
  unchanged
- the subject loses its toolchain-scripts prefix, since that file is no
  longer touched
- drop the paragraph citing the kernel proposal
---
 meta/lib/oeqa/sdk/cases/kmod.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/meta/lib/oeqa/sdk/cases/kmod.py b/meta/lib/oeqa/sdk/cases/kmod.py
index 1be23e994fd2..a55071a3e79a 100644
--- a/meta/lib/oeqa/sdk/cases/kmod.py
+++ b/meta/lib/oeqa/sdk/cases/kmod.py
@@ -26,8 +26,12 @@ class KernelModuleTest(OESDKTestCase):
         parallel_make = "-j %d" % (pmv) if pmv else ""
 
         self.ensure_target_package("kernel-devsrc")
+        # the kernel assigns HOSTPKG_CONFIG with '=', so it has to come from
+        # the make command line, and kernel.bbclass already gives its own
+        # host tools this same wrapper
+        host_pkg_config = 'HOSTPKG_CONFIG="pkg-config-native"'
         # These targets need to be built before kernel modules can be built.
-        self._run("make %s -C $OECORE_TARGET_SYSROOT/usr/src/kernel prepare scripts" % (parallel_make))
+        self._run("make %s %s -C $OECORE_TARGET_SYSROOT/usr/src/kernel prepare scripts" % (parallel_make, host_pkg_config))
 
         with tempfile.TemporaryDirectory(prefix="cryptodev", dir=self.tc.sdk_dir) as testdir:
             git_url = "https://github.com/cryptodev-linux/cryptodev-linux"
@@ -39,5 +43,5 @@ class KernelModuleTest(OESDKTestCase):
             self.assertTrue(os.path.isdir(sourcedir))
             subprocess.check_output(["git", "-C", sourcedir, "checkout", git_sha], stderr=subprocess.STDOUT)
 
-            self._run("make -C %s V=1 KERNEL_DIR=$OECORE_TARGET_SYSROOT/usr/src/kernel" % sourcedir)
+            self._run("make -C %s V=1 %s KERNEL_DIR=$OECORE_TARGET_SYSROOT/usr/src/kernel" % (sourcedir, host_pkg_config))
             self.check_elf(os.path.join(sourcedir, "cryptodev.ko"))
-- 
2.50.0.173.g8b6f19ccfc3a