giflib: don't build HTML documentation

pkgs/development/libraries/giflib/default.nix

@@ -4,7 +4,6 @@
 , fetchpatch
 , fixDarwinDylibNames
 , pkgsStatic
-, imagemagick_light
 }:
 
 stdenv.mkDerivation rec {
@@ -29,9 +28,7 @@ stdenv.mkDerivation rec {
     ./mingw-install-exes.patch
   ];
 
-  nativeBuildInputs = [
-    imagemagick_light
-  ] ++ lib.optionals stdenv.isDarwin [
+  nativeBuildInputs = lib.optionals stdenv.isDarwin [
     fixDarwinDylibNames
   ];
 
@@ -39,7 +36,11 @@ stdenv.mkDerivation rec {
     "PREFIX=${builtins.placeholder "out"}"
   ];
 
-  postPatch = lib.optionalString stdenv.hostPlatform.isStatic ''
+  postPatch = ''
+    # we don't want to build HTML documentation
+    substituteInPlace doc/Makefile \
+      --replace-fail "all: allhtml manpages" "all: manpages"
+  '' + lib.optionalString stdenv.hostPlatform.isStatic ''
     # Upstream build system does not support NOT building shared libraries.
     sed -i '/all:/ s/$(LIBGIFSO)//' Makefile
     sed -i '/all:/ s/$(LIBUTILSO)//' Makefile