https://bugs.gentoo.org/show_bug.cgi?id=428494
should be obsolete with >=dev-util/pkgconf-0.8.4
--- configure.ac+++ configure.ac@@ -76,7 +76,6 @@# Check for pkg-config
PKG_PROG_PKG_CONFIG
-AC_PROG_VERSION_CHECK([pkg-config], [0.9])# Check for compiler