package/perl-extutils-pkgconfig: new package

host-perl-extutils-pkgconfig is needed by perl-gd to find gd in version
2.3.0

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Acked-by: Francois Perrad <francois.perrad@gadz.org>
[Arnout:
 - remove Config.in - it's host-only
 - add DEVELOPERS entry
 - use HOST_PERL_EXTUTILS_PKGCONFIG_DEPENDENCIES]
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>