Add Recommends on syslinux-utils

In case a user wants to use SPLASHPNG and hence ppmtolss16) for their
own splash images. Closes: #768977

debian/changelog

@@ -26,6 +26,8 @@ debian-cd (3.1.18) UNRELEASED; urgency=medium
   * Switch references to d-i.debian.org to use https instead of http.
     Closes: #809698. Also use --ca-directory /etc/ssl/ca-debian/ with wget
     to ensure this works.
+  * Add Recommends: syslinux-utils in case a user wants to use SPLASHPNG
+    (and hence ppmtolss16) for their own splash images. Closes: #768977
 
   [ Didier Raboud ]
   * For stretch, swap amd64 and i386 to let the first be the norm, and the

debian/control

@@ -12,7 +12,7 @@ Vcs-Browser: http://anonscm.debian.org/git/debian-cd/debian-cd.git;a=summary
 Package: debian-cd
 Architecture: all
 Depends: ${misc:Depends}, curl, perl, dpkg-dev, cpp, libdigest-md5-perl, libdigest-sha-perl, tofrodos, apt (>= 0.3.11.1), make, xorriso | genisoimage, lynx-cur | lynx, grep-dctrl, bc, libcompress-zlib-perl, bzip2, libdpkg-perl
-Recommends: hfsutils, netpbm, isolinux, syslinux-common, syslinux-utils, mtools, dosfstools
+Recommends: hfsutils, netpbm, isolinux, syslinux-common, syslinux-utils, mtools, dosfstools, syslinux-utils
 Description: Tools for building (Official) Debian CD set
  Debian-cd is the official tool for building Debian CD set since the potato
  release. It was formerly called YACS (for Yet Another CD Script).