package/pkgconf: add patch to restore pre-1.5.3 behavior for sysroot prefixing

package/pkgconf: add patch to restore pre-1.5.3 behavior for sysroot prefixing

Prior to the bump to version 1.5.3 in commit
4e423669399ad8389edd81761ea5c9cc26bf312d, we had a patch on pkgconf
that ensures only some variables containing paths were prefixed by the
sysroot directory when queried through pkg-config. This patch was
dropped as part of the 1.5.3 bump, but it turns out we really need
something like this, or a significant number of changes need to be
done to existing packages.

Indeed, pkg-config has no notion of which variable/path gets used at
build time vs. which variable/path gets used at runtime. Prefixing
with the sysroot the paths used at build time works and is desirable,
but prefixing the paths used at runtime doesn't work.

This commit should fix a large number of remaining build failures
related to pkgconf 1.5.3, and should allow reverting a significant
number of workarounds.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>