pkg-config was skipping every other link flag due to a list manipulation bug,
backport a commit from git to fix this.
This will stop users of zlib.pc from inserting the sysroot directory indirectly
into builds.
(From OE-Core rev: df3ecaf86360a9c109b1b19bfa8a52890315bbdc)
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
