Remove separate targets for classic and filament renderer.

The platform::Renderer now supports both implementations at
runtime.

PiperOrigin-RevId: 878427862
Change-Id: I2997c197c6eddbe177c77b435cc5848fd80f1839

src/experimental/filament/CMakeLists.txt

@@ -21,7 +21,6 @@ target_compile_definitions(${MUJOCO_FILAMENT_TARGET_NAME} PRIVATE MJ_STATIC)
 
 target_sources(${MUJOCO_FILAMENT_TARGET_NAME}
     PUBLIC
-        mjr_compat.cc
         render_context_filament.h
         render_context_filament.cc
         filament/buffer_util.cc
@@ -58,6 +57,13 @@ target_sources(${MUJOCO_FILAMENT_TARGET_NAME}
         filament/vertex_util.cc
         filament/vertex_util.h
 )
+if(MUJOCO_USE_FILAMENT_MJR_COMPAT)
+    target_sources(${MUJOCO_FILAMENT_TARGET_NAME}
+        PUBLIC
+            mjr_compat.cc
+    )
+endif()
+
 target_include_directories(${MUJOCO_FILAMENT_TARGET_NAME}
     PUBLIC
         ${PROJECT_SOURCE_DIR}/include