blender: extract conditionals to variables for reuse

This gives them some greater semantic meaning, easing understanding (and
we will reuse them more soon). In some places, remove duplicate
inclusion of the deps in different conditionals to unify them (i.e.,
include them once based on one conditional, instead of under multiple
separate conditionals).

pkgs/applications/misc/blender/default.nix

@@ -84,6 +84,10 @@
 }:
 
 let
+  embreeSupport = (!stdenv.isAarch64 && stdenv.isLinux) || stdenv.isDarwin;
+  openImageDenoiseSupport = (!stdenv.isAarch64 && stdenv.isLinux) || stdenv.isDarwin;
+  openUsdSupport = !stdenv.isDarwin;
+
   python3 = python3Packages.python;
   pyPkgsOpenusd = python3Packages.openusd.override { withOsl = false; };
 
@@ -193,7 +197,7 @@ stdenv.mkDerivation (finalAttrs: {
       "-DWITH_GHOST_WAYLAND_DYNLOAD=OFF"
       "-DWITH_GHOST_WAYLAND_LIBDECOR=ON"
     ]
-    ++ lib.optionals (stdenv.hostPlatform.isAarch64 && stdenv.hostPlatform.isLinux) [
+    ++ lib.optionals (!embreeSupport) [
       "-DWITH_CYCLES_EMBREE=OFF"
     ]
     ++ lib.optionals stdenv.isDarwin [
@@ -269,10 +273,8 @@ stdenv.mkDerivation (finalAttrs: {
       zlib
       zstd
     ]
-    ++ lib.optionals (!stdenv.isAarch64 && stdenv.isLinux) [
-      embree
-      (openimagedenoise.override { inherit cudaSupport; })
-    ]
+    ++ lib.optional embreeSupport embree
+    ++ lib.optional openImageDenoiseSupport (openimagedenoise.override { inherit cudaSupport; })
     ++ (
       if (!stdenv.isDarwin) then
         [
@@ -296,9 +298,7 @@ stdenv.mkDerivation (finalAttrs: {
           OpenGL
           SDL
           brotli
-          embree
           llvmPackages.openmp
-          (openimagedenoise.override { inherit cudaSupport; })
           sse2neon
         ]
     )
@@ -325,7 +325,7 @@ stdenv.mkDerivation (finalAttrs: {
       ps.requests
       ps.zstandard
     ]
-    ++ lib.optionals (!stdenv.isDarwin) [ pyPkgsOpenusd ];
+    ++ lib.optional openUsdSupport [ pyPkgsOpenusd ];
 
   blenderExecutable =
     placeholder "out"