pkg-config: fix gcc6 build (bootstrap)

srcpkgs/pkg-config/template

@@ -1,13 +1,20 @@
 # Template build file for 'pkg-config'
 pkgname=pkg-config
 version=0.29.1
-revision=1
+revision=2
 bootstrap=yes
 build_style=gnu-configure
 configure_args="--with-internal-glib --disable-host-tool"
+# required for gcc6 bootstrap
+hostmakedepends="gcc"
 short_desc="System for managing library compile/link flags"
 maintainer="Juan RP <xtraeme@voidlinux.eu>"
 homepage="http://pkgconfig.freedesktop.org/wiki/"
 license="GPL-2"
 distfiles="http://pkgconfig.freedesktop.org/releases/$pkgname-$version.tar.gz"
 checksum=beb43c9e064555469bd4390dcfd8030b1536e0aa103f08d7abf7ae8cac0cb001
+
+_gccver=$(gcc --version | awk '/gcc \(GCC\)/{ print $3 }')
+if [ "${_gccver%%.*}" -gt 5 ]; then
+	CFLAGS="-Wno-error=format-nonliteral"
+fi