File build/make-kit-win64 from the latest check-in

#! /bin/sh

AR=x86_64-w64-mingw32-ar
CC=x86_64-w64-mingw32-gcc
CXX=x86_64-w64-mingw32-g++
RANLIB=x86_64-w64-mingw32-ranlib
RC=x86_64-w64-mingw32-windres
STRIP="${STRIP:-x86_64-w64-mingw32-strip}"
export AR CC CXX RANLIB RC STRIP

PKG_CONFIG_PATH='/dev/null/null'
PKG_CONFIG_DIR='/dev/null/null';
PKG_CONFIG_LIBDIR='/home/rkeene/root/cross-compilers/x86_64-w64-mingw32/x86_64-w64-mingw32/lib/pkgconfig';
export PKG_CONFIG_PATH PKG_CONFIG_DIR PKG_CONFIG_LIBDIR

./kitcreator "$@" --host=x86_64-w64-mingw32