Add separate build step for OpenUSD to third_party_deps.

This will fetch and call the build_usd.py build helper for OpenUSD and build within the MuJoCo _deps folder. Simplifying the build process for MuJoCo with USD. Users can still provide their own USD build, but must now do so via pxr_DIR.

PiperOrigin-RevId: 846735578
Change-Id: I0da7eb2da6465e2d518084340e762bf370adb6d5

simulate/CMakeLists.txt

@@ -185,7 +185,7 @@ if(SIMULATE_BUILD_EXECUTABLE)
     target_link_libraries(simulate "-framework CoreVideo")
   endif()
 
-  if (MUJOCO_WITH_USD)
+  if (BUILD_WITH_USD)
     # pxr/usd/tf/hashset.h might include deprecated headers so disable this check
     # when compiling with USD enabled.
     target_compile_options(
@@ -265,8 +265,13 @@ if(SIMULATE_BUILD_EXECUTABLE)
       MUJOCO_ENABLE_RPATH
     )
 
-    if (MUJOCO_WITH_USD)
-      target_compile_definitions(simulate PUBLIC mjUSEUSD)
+    if (BUILD_WITH_USD)
+      # pxr/usd/tf/hashset.h might include deprecated headers so disable this check
+      # when compiling with USD enabled.
+      target_compile_options(
+         simulate
+         PRIVATE -Wno-deprecated
+      )
 
       # Add support to RPATH for the samples.
       target_add_rpath(
@@ -275,10 +280,13 @@ if(SIMULATE_BUILD_EXECUTABLE)
         INSTALL_DIRECTORY
         "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_BINDIR}"
         LIB_DIRS
-        ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}/mujocoUsd ${USD_DIR}/lib
         DEPENDS
         MUJOCO_ENABLE_RPATH
       )
+
+      # Do we need this?
+      #target_link_options(simulate PRIVATE -rpath=${pxr_DIR}/lib)
+
     endif()
 
     if(NOT MUJOCO_SIMULATE_USE_SYSTEM_GLFW)