Enable MuJoCo Studio build and packaging on macos.

Also:
- Packages MuJoCo Studio as MuJoCoStudio.app in the MuJoCo.dmg.
- Fixes a Filament compile issue.
- Patches libwebp to fix compile error related to universal builds and forces
  it to build as static.
- Removes the separate, obsolete "build_studio" step.
PiperOrigin-RevId: 934564785
Change-Id: I50c83283b5e138062e37d53926a5a77fdf99dbfa

cmake/libwebp-apple-float16.patch

@@ -0,0 +1,8 @@
+diff --git a/cmake/cpu.cmake b/cmake/cpu.cmake
+--- a/cmake/cpu.cmake
++++ b/cmake/cpu.cmake
+@@ -121,3 +121,3 @@
+     # Explicitly disable SIMD.
+-    if(SIMD_DISABLE_FLAGS)
++    if(SIMD_DISABLE_FLAGS AND NOT APPLE)
+       list(GET SIMD_DISABLE_FLAGS ${I_SIMD} SIMD_COMPILE_FLAG)

cmake/third_party_deps/filament.cmake

@@ -32,6 +32,11 @@ else()
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -include cstring -include optional")
 endif()
 
+# Filament generates deprecated warnings on MacOS.
+if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-error=deprecated-declarations")
+endif()
+
 set(FILAMENT_ENABLE_EXPERIMENTAL_GCC_SUPPORT ON)
 set(FILAMENT_SKIP_SDL2 ON)
 set(FILAMENT_USE_EXTERNAL_ABSL ON)

cmake/third_party_deps/libwebp.cmake

@@ -20,9 +20,21 @@ mark_as_advanced(MUJOCO_DEP_VERSION_libwebp)
 
 include(FindOrFetch)
 
+set(LIBWEBP_PATCH_COMMAND
+  git apply --reject --whitespace=fix ${mujoco_SOURCE_DIR}/cmake/libwebp-apple-float16.patch
+)
+
+set(BUILD_SHARED_LIBS_OLD ${BUILD_SHARED_LIBS})
+set(BUILD_SHARED_LIBS OFF)
+
 fetchpackage(
     PACKAGE_NAME  libwebp
     GIT_REPO      https://github.com/webmproject/libwebp.git
     GIT_TAG       ${MUJOCO_DEP_VERSION_libwebp}
     TARGETS       webp
+    PATCH_COMMAND ${LIBWEBP_PATCH_COMMAND}
 )
+
+set(BUILD_SHARED_LIBS ${BUILD_SHARED_LIBS_OLD})
+
+