Cleanup: Fix build warnings and errors after recent commits

- Add missing include for `std::function` without TBB
- Add include for math define reported in chat (couldn't reproduce that)

source/blender/blenlib/BLI_enumerable_thread_specific.hh

@@ -23,6 +23,7 @@
 #  endif
 #else
 #  include <atomic>
+#  include <functional>
 #  include <mutex>
 
 #  include "BLI_map.hh"

source/blender/makesrna/intern/rna_cloth.cc

@@ -9,6 +9,8 @@
 #include <climits>
 #include <cstdlib>
 
+#include "BLI_math_base.h"
+
 #include "DNA_cloth_types.h"
 #include "DNA_object_types.h"
 #include "DNA_scene_types.h"