Build: add WITH_OPENVDB_3_ABI_COMPATIBLE option.

Better fix for T54457. It seems Debian compiles OpenVDB without ABI 3
compatibility, while Arch does enable it as is the default in the OpeVDB
CMake build system.

So now there's an option that the distribution can set depending on how
they compile their OpenVDB package.

intern/openvdb/CMakeLists.txt

@@ -38,9 +38,14 @@ set(SRC
 if(WITH_OPENVDB)
 	add_definitions(
 		-DWITH_OPENVDB
-		-DOPENVDB_3_ABI_COMPATIBLE
 	)
 
+	if(WITH_OPENVDB_3_ABI_COMPATIBLE)
+		add_definitions(
+			-DOPENVDB_3_ABI_COMPATIBLE
+		)
+	endif()
+
 	list(APPEND INC_SYS
 		${BOOST_INCLUDE_DIR}
 		${TBB_INCLUDE_DIRS}

intern/openvdb/intern/openvdb_writer.cc

@@ -45,7 +45,7 @@ void OpenVDBWriter::insert(const openvdb::GridBase::Ptr &grid)
 
 void OpenVDBWriter::insert(const openvdb::GridBase &grid)
 {
-#if (OPENVDB_LIBRARY_MAJOR_VERSION_NUMBER >= 3)
+#if (OPENVDB_LIBRARY_MAJOR_VERSION_NUMBER <= 3) || defined(OPENVDB_3_ABI_COMPATIBLE)
 	m_grids->push_back(grid.copyGrid());
 #else
 	m_grids->push_back(grid.copyGridWithNewTree());