imagemagick: unbreak for aarch64

With the newly added libjxl dependency it was broken, since libjxl
doesn't build on aarch64. Remove that dependency if we're building for
aarch64 for now, until the compiler / library is fixed.

pkgs/applications/graphics/ImageMagick/7.0.nix

@@ -37,7 +37,9 @@ stdenv.mkDerivation rec {
     ++ (if arch != null then [ "--with-gcc-arch=${arch}" ] else [ "--without-gcc-arch" ])
     ++ lib.optional (librsvg != null) "--with-rsvg"
     ++ lib.optional (liblqr1 != null) "--with-lqr"
-    ++ lib.optional (libjxl != null) "--with-jxl"
+    # libjxl is broken on aarch64 (see meta.broken in libjxl) for now,
+    # let's disable it for now to unbreak the imagemagick build.
+    ++ lib.optional (libjxl != null && !stdenv.isAarch64) "--with-jxl"
     ++ lib.optionals (ghostscript != null)
       [ "--with-gs-font-dir=${ghostscript}/share/ghostscript/fonts"
         "--with-gslib"
@@ -50,8 +52,12 @@ stdenv.mkDerivation rec {
 
   buildInputs =
     [ zlib fontconfig freetype ghostscript
-      libjxl liblqr1 libpng libtiff libxml2 libheif djvulibre
+      liblqr1 libpng libtiff libxml2 libheif djvulibre
     ]
+    # libjxl is broken on aarch64 (see meta.broken in libjxl) for now,
+    # let's disable it for now to unbreak the imagemagick build.
+    ++ lib.optionals (!stdenv.isAarch64)
+      [ libjxl ]
     ++ lib.optionals (!stdenv.hostPlatform.isMinGW)
       [ openexr librsvg openjpeg ]
     ++ lib.optionals stdenv.isDarwin [