libbpf: use pkg-config

The libbpf makefile uses pkg-config to get the libelf build flags and
file paths.
Inherit pkgconfig so the install target can copy the binaries in the
sysroot, which are needed by other packages, like bcc.

Signed-off-by: Matteo Croce <mcroce@microsoft.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-oe/recipes-kernel/libbpf/libbpf_0.3.bb

@@ -23,6 +23,8 @@ S = "${WORKDIR}/git/src"
 
 EXTRA_OEMAKE += "DESTDIR=${D} LIBDIR=${libdir}"
 
+inherit pkgconfig
+
 do_compile() {
 	if grep -q "CONFIG_BPF_SYSCALL=y" ${STAGING_KERNEL_BUILDDIR}/.config
 	then
@@ -40,5 +42,3 @@ do_install() {
 		bbnote "no files to install"
 	fi
 }
-
-BBCLASSEXTEND = "native"