libspatialindex: fix on Darwin

Recent bump to 2.1.0 changed the soversion from 7 to 8. It broke
python3-rtree as follows:

OSError: Could not load libspatialindex_c library

Instead of bumping the version in postFixup, disable rpath in cmake
instructions.

Co-Authored-By: Reno Dakota <[e-mail]>

pkgs/by-name/li/libspatialindex/no-rpath-for-darwin.diff

···
+--- a/src/CMakeLists.txt
++++ b/src/CMakeLists.txt
+@@ -248,7 +248,7 @@ if(HAVE_BCOPY)
+ endif()
+ 
+ 
+-if(APPLE)
++if(FALSE)
+   set(MACOSX_RPATH ON)
+   set_target_properties(spatialindex spatialindex_c
+                         PROPERTIES INSTALL_NAME_DIR "@rpath")

pkgs/by-name/li/libspatialindex/package.nix

···
   stdenv,
   fetchFromGitHub,
   cmake,
-  fixDarwinDylibNames,
 }:
 
 stdenv.mkDerivation (finalAttrs: {
···
     hash = "sha256-a2CzRLHdQMnVhHZhwYsye4X644r8gp1m6vU2CJpSRpU=";
   };
 
+  patches = [
+    ./no-rpath-for-darwin.diff
+  ];
+
   postPatch = ''
     patchShebangs test/
   '';
 
-  nativeBuildInputs = [ cmake ] ++ lib.optional stdenv.hostPlatform.isDarwin fixDarwinDylibNames;
+  nativeBuildInputs = [ cmake ];
 
   cmakeFlags = [
     (lib.cmakeBool "BUILD_TESTING" finalAttrs.finalPackage.doCheck)
···
   ];
 
   doCheck = true;
-
-  postFixup = lib.optionalString stdenv.hostPlatform.isDarwin ''
-    install_name_tool -change "@rpath/libspatialindex.7.dylib" "$out/lib/libspatialindex.7.dylib" $out/lib/libspatialindex_c.dylib
-  '';
 
   meta = {
     description = "Extensible spatial index library in C++";