Gperf is now a hard dependency.
* gnu/packages/patches/fontconfig-remove-debug-printf.patch: New file.
* gnu/local.mk (dist_patch_DATA): Register it.
* gnu/packages/fontutils.scm (fontconfig): Update to 2.12.6.
[source]: Add 'fontconfig-remove-debug-printf.patch'.
[arguments]: Remove 'regenerate-fcobjshash' phase.