libubox: Inherit pkgconfig
libubox: Inherit pkgconfig

Fixes
TOPDIR/build/tmp/work/cortexa15t2hf-neon-yoe-linux-gnueabi/libubox/1.0.1+gitAUTOINC+07413cce72-r0/git/blobmsg_json.c:23:11: fatal error: 'json/json.h' file not found
        #include <json/json.h>
                 ^~~~~~~~~~~~~

Signed-off-by: Khem Raj <729d64b6f67515e258459a5f6d20ec88b2caf8df@gmail.com>

openembedded/meta-openembedded,schnitzeltony/meta-openembedded,rehsack/meta-openembedded,schnitzeltony/meta-openembedded,openembedded/meta-openembedded,schnitzeltony/meta-openembedded,moto-timo/meta-openembedded,moto-timo/meta-openembedded,schnitzeltony/meta-openembedded,openembedded/meta-openembedded,openembedded/meta-openembedded,openembedded/meta-openembedded,rehsack/meta-openembedded,openembedded/meta-openembedded,moto-timo/meta-openembedded,rehsack/meta-openembedded,rehsack/meta-openembedded,schnitzeltony/meta-openembedded,moto-timo/meta-openembedded,moto-timo/meta-openembedded,openembedded/meta-openembedded,schnitzeltony/meta-openembedded,schnitzeltony/meta-openembedded,openembedded/meta-openembedded,rehsack/meta-openembedded,rehsack/meta-openembedded,rehsack/meta-openembedded