[hje1@archlaptop libpng12]$ ls
libpng-1.2.52-apng.patch.gz  libpng-1.2.52.tar.xz  PKGBUILD  src
[hje1@archlaptop libpng12]$ LANG=en_DK.UTF-8 makepkg -si
==> Making package: libpng12 1.2.52-1 (Mon Feb 16 19:31:53 CET 2015)
==> Checking runtime dependencies...
==> Checking buildtime dependencies...
==> Retrieving sources...
  -> Found libpng-1.2.52.tar.xz
  -> Found libpng-1.2.52-apng.patch.gz
==> Validating source files with md5sums...
    libpng-1.2.52.tar.xz ... FAILED
    libpng-1.2.52-apng.patch.gz ... FAILED
==> ERROR: One or more files did not pass the validity check!