Actually remove libpng's public headers when the project is cleaned -.-
Actually remove libpng's public headers when the project is cleaned -.-

thpatch/thcrap,VBChunguk/thcrap,VBChunguk/thcrap,thpatch/thcrap,thpatch/thcrap,thpatch/thcrap,VBChunguk/thcrap,thpatch/thcrap