gnu: fontconfig: Update to 2.12.6.

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.

gnu/local.mk

@@ -636,6 +636,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/fltk-xfont-on-demand.patch		\
   %D%/packages/patches/foomatic-filters-CVE-2015-8327.patch	\
   %D%/packages/patches/foomatic-filters-CVE-2015-8560.patch	\
+  %D%/packages/patches/fontconfig-remove-debug-printf.patch	\
   %D%/packages/patches/freeimage-CVE-2015-0852.patch		\
   %D%/packages/patches/freeimage-CVE-2016-5684.patch		\
   %D%/packages/patches/freeimage-fix-build-with-gcc-5.patch	\

gnu/packages/fontutils.scm

@@ -230,20 +230,21 @@ fonts to/from the WOFF2 format.")
 (define-public fontconfig
   (package
    (name "fontconfig")
-   (version "2.12.3")
+   (version "2.12.6")
    (source (origin
             (method url-fetch)
             (uri (string-append
                    "https://www.freedesktop.org/software/fontconfig/release/fontconfig-"
                    version ".tar.bz2"))
+            (patches (search-patches "fontconfig-remove-debug-printf.patch"))
             (sha256 (base32
-                     "1ggq6jmz3mlzk4xjs615aqw9h3hq33chjn82bhli26kk09kby95x"))))
+                     "05zh65zni11kgnhg726gjbrd55swspdvhqbcnj5a5xh8gn03036g"))))
    (build-system gnu-build-system)
    (propagated-inputs `(("expat" ,expat)
                         ("freetype" ,freetype)))
    (inputs `(("gs-fonts" ,gs-fonts)))
    (native-inputs
-    `(("gperf" ,gperf) ; Try dropping this for > 2.12.3.
+    `(("gperf" ,gperf)
       ("pkg-config" ,pkg-config)))
    (arguments
     `(#:configure-flags
@@ -262,13 +263,6 @@ fonts to/from the WOFF2 format.")
             "PYTHON=false")
       #:phases
       (modify-phases %standard-phases
-        (add-before 'configure 'regenerate-fcobjshash
-          ;; XXX The pre-generated gperf files are broken.
-          ;; See <https://bugs.freedesktop.org/show_bug.cgi?id=101280>.
-          (lambda _
-            (delete-file "src/fcobjshash.h")
-            (delete-file "src/fcobjshash.gperf")
-            #t))
         (replace 'install
                  (lambda _
                    ;; Don't try to create /var/cache/fontconfig.

gnu/packages/patches/fontconfig-remove-debug-printf.patch

@@ -0,0 +1,18 @@
+Fontconfig 2.12.5 and 2.12.6 was released with a stray debugging statement.
+See <https://lists.freedesktop.org/archives/fontconfig/2017-October/006079.html>.
+
+Patch copied from upstream source repository:
+https://cgit.freedesktop.org/fontconfig/commit/?id=b56207a069be2574df455ede0a6ab61f44d5ca2b
+
+diff --git a/fc-query/fc-query.c b/fc-query/fc-query.c
+index 842a8b6..6cd5abd 100644
+--- a/fc-query/fc-query.c
++++ b/fc-query/fc-query.c
+@@ -170,7 +170,6 @@ main (int argc, char **argv)
+ 	    FcPattern *pat;
+ 
+ 	    id = ((instance_num << 16) + face_num);
+-	    printf("id %d\n", id);
+ 	    if (FT_New_Face (ftLibrary, argv[i], id, &face))
+ 	      break;
+ 	    num_faces = face->num_faces;