Merge: redhat: pass correct RPM_VMLINUX_H to bpftool install

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/4299

redhat: pass correct RPM_VMLINUX_H to bpftool install
    
This is required to fix occasional racy build failures where the lack
of a correctly specified path to vmlinux.h in the %install phase can
cause the bpf Makefile to try and re-generate it against the
build-host kernel; the mistmatched built tools and host kernel can
then crash, aborting the build.  To add to the fun of this, it's
somewhat randomly tied to when bpf /sys/ files have updated
timestamps to trigger the make dependency.
    
By saving the file and referencing in the %install phase, we bypass
all this.
   
JIRA: INTERNAL  
Upstream-status: https://gitlab.com/cki-project/kernel-ark  
Related-issue: https://gitlab.com/cki-project/kernel-arkproject/infrastructure/-/issues/340  
Related-MR: https://gitlab.com/cki-project/kernel-ark/-/merge_requests/3105  
Link: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/commit/?id=e7b64f9d3f5b10186038201e0b91f734cbd7fc3d

Signed-off-by: Ian Wienand <iwienand@redhat.com>

Approved-by: Jan Stancek <jstancek@redhat.com>
Approved-by: Patrick Talbert <ptalbert@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Lucas Zampieri <lzampier@redhat.com>

Author: zampierilucas

redhat/kernel.spec.template

@@ -2720,6 +2720,7 @@ popd
 if [ -f $DevelDir/vmlinux.h ]; then
   RPM_VMLINUX_H=$DevelDir/vmlinux.h
 fi
+echo "${RPM_VMLINUX_H}" > ../vmlinux_h_path
 
 %if %{with_bpftool}
 %global bpftool_make \
@@ -2876,6 +2877,9 @@ find Documentation -type d | xargs chmod u+w
 
 cd linux-%{KVERREL}
 
+# re-define RPM_VMLINUX_H, because it doesn't carry over from %build
+RPM_VMLINUX_H="$(cat ../vmlinux_h_path)"
+
 %if %{with_doc}
 docdir=$RPM_BUILD_ROOT%{_datadir}/doc/kernel-doc-%{specversion}-%{pkgrelease}