Re-add pkg-config to linux and windows images
Re-add pkg-config to linux and windows images

larskanis/rake-compiler-dock,rake-compiler/rake-compiler-dock,larskanis/rake-compiler-dock,rake-compiler/rake-compiler-dock,rake-compiler/rake-compiler-dock,rake-compiler/rake-compiler-dock,rake-compiler/rake-compiler-dock,larskanis/rake-compiler-dock