Build environment: Update OpenSubdiv to 3.4.0 RC 2

Newer OpenSubdiv brings fixes and improvements for non-manifold meshes,
which fixes some crashes we've experienced in the recent past when using
Gregory patches.

Additionally, thing new version of OpenSubdiv brings sparse patches,
which allows to multi-thread topology refinement step.

build_files/build_environment/cmake/opensubdiv.cmake

@@ -70,7 +70,6 @@ ExternalProject_Add(external_opensubdiv
   DOWNLOAD_DIR ${DOWNLOAD_DIR}
   URL_HASH MD5=${OPENSUBDIV_Hash}
   PREFIX ${BUILD_DIR}/opensubdiv
-  PATCH_COMMAND ${PATCH_CMD} --verbose -p 1 -N -d ${BUILD_DIR}/opensubdiv/src/external_opensubdiv < ${PATCH_DIR}/opensubdiv.diff
   CMAKE_ARGS -DCMAKE_INSTALL_PREFIX=${LIBDIR}/opensubdiv -Wno-dev ${DEFAULT_CMAKE_FLAGS} ${OPENSUBDIV_EXTRA_ARGS}
   INSTALL_DIR ${LIBDIR}/opensubdiv
 )

build_files/build_environment/cmake/versions.cmake

@@ -105,8 +105,8 @@ set(CUEW_GIT_UID 1744972026de9cf27c8a7dc39cf39cd83d5f922f)
 set(CUEW_URI https://github.com/CudaWrangler/cuew/archive/${CUEW_GIT_UID}.zip)
 set(CUEW_HASH 86760d62978ebfd96cd93f5aa1abaf4a)
 
-set(OPENSUBDIV_VERSION v3_3_3)
-set(OPENSUBDIV_Hash 29c79dc01ef616aab02670bed5544ddd)
+set(OPENSUBDIV_VERSION v3_4_0_RC2)
+set(OPENSUBDIV_Hash f6a10ba9efaa82fde86fe65aad346319)
 set(OPENSUBDIV_URI https://github.com/PixarAnimationStudios/OpenSubdiv/archive/${OPENSUBDIV_VERSION}.tar.gz)
 
 set(SDL_VERSION 2.0.8)

build_files/build_environment/patches/opensubdiv.diff

@@ -1,13 +0,0 @@
-diff --git a/opensubdiv/far/topologyRefiner.cpp b/opensubdiv/far/topologyRefiner.cpp
-index 3754b36e..7fe42bcc 100644
---- a/opensubdiv/far/topologyRefiner.cpp
-+++ b/opensubdiv/far/topologyRefiner.cpp
-@@ -263,7 +263,7 @@ namespace internal {
-         bool IsEmpty() const { return *((int_type*)this) == 0; }
- 
-         FeatureMask() { Clear(); }
--        FeatureMask(Options const & options, Sdc::SchemeType sType) { InitializeFeatures(options, sType); }
-+        FeatureMask(Options const & options, Sdc::SchemeType sType) { Clear(); InitializeFeatures(options, sType); }
- 
-         //  These are the two primary methods intended for use -- intialization via a set of Options
-         //  and reduction of the subsequent feature set (which presumes prior initialization with the