openjpeg: Correctly set the install name on darwin

This fixes libpoppler, and thus texLiveFull

pkgs/development/libraries/openjpeg/generic.nix

···
     (mkFlag jp3dSupport "BUILD_JP3D")
     (mkFlag thirdPartySupport "BUILD_THIRDPARTY")
     (mkFlag testsSupport "BUILD_TESTING")
+  ] ++ stdenv.lib.optionals stdenv.isDarwin
+  [ "-DCMAKE_INSTALL_NAME_DIR=\${CMAKE_INSTALL_PREFIX}/lib"
   ];
 
   nativebuildInputs = [ pkgconfig ];