devtools: test static linkage with pkg-config

The pkg-config file was tested by building some of the examples using make,
pulling the cflags and ldflags from the pkg-config file for DPDK. However,
this only tested the shared library linkage, and not the static, so this
patch updates it to test both.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Luca Boccassi <bluca@debian.org>
Acked-by: Sunil Pai G <sunil.pai.g@intel.com>