Fix #107390: Image transformation in VSE is very slow

71d7c919c0 introduced usage of `threading::parallel_for()`, but
`WITH_TBB` was not defined for imbuf module.

source/blender/imbuf/CMakeLists.txt

@@ -158,6 +158,18 @@ if(WITH_IMAGE_WEBP)
   add_definitions(-DWITH_WEBP)
 endif()
 
+if(WITH_TBB)
+  add_definitions(-DWITH_TBB)
+
+  list(APPEND INC_SYS
+    ${TBB_INCLUDE_DIRS}
+  )
+
+  list(APPEND LIB
+    ${TBB_LIBRARIES}
+  )
+endif()
+
 list(APPEND INC
   ../../../intern/opencolorio
 )