swupdate: inherit pkgconfig
swupdate's makefile calls pkgconfig, but with no explicit
dependency on the native tool, after the introduction
of recipe-specific sysroot in oe-core, pkconfig cannot be found
and the build fails.
Log data follows:
| DEBUG: Executing shell function do_compile
| NOTE: make -j 8 V=1 ARCH=arm CROSS_COMPILE=arm-poky-linux-gnueabi-
SKIP_STRIP=y swupdate_unstripped
| make -f /home/gizero/work/smartliving/distro/repo-master/build-poky/
tmp/work/cortexa7hf-neon-vfpv4-poky-linux-gnueabi/swupdate/2017.01-r0/
git/Makefile silentoldconfig
| make -f scripts/Makefile.build obj=scripts/basic
| mkdir -p include/linux include/config
| make -f scripts/Makefile.build obj=scripts/kconfig silentoldconfig
| mkdir -p include/config include/generated
| scripts/kconfig/conf --silentoldconfig Kconfig
| /bin/sh: 1: pkg-config: not found
| /bin/sh: 1: pkg-config: not found
| /bin/sh: 1: pkg-config: not found
Inheriting pkgconfig class fixes it.
Signed-off-by: Andrea Galbusera <gizero@gmail.com>