Install vmlinux.h

As requested by Christian, to build downstream BPF programs for the
kernel.

See: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2050083

PKGBUILD

@@ -82,6 +82,7 @@ prepare() {
 build() {
   cd $_srcname
   make all
+  make -C tools/bpf/bpftool vmlinux.h feature-clang-bpf-co-re=1
   make htmldocs
 }
 
@@ -134,7 +135,7 @@ _package-headers() {
 
   echo "Installing build files..."
   install -Dt "$builddir" -m644 .config Makefile Module.symvers System.map \
-    localversion.* version vmlinux
+    localversion.* version vmlinux tools/bpf/bpftool/vmlinux.h
   install -Dt "$builddir/kernel" -m644 kernel/Makefile
   install -Dt "$builddir/arch/x86" -m644 arch/x86/Makefile
   cp -t "$builddir" -a scripts