Added a note about disabling LTO

tools/python/CMakeLists.txt

@@ -5,6 +5,11 @@ set(USE_SSE4_INSTRUCTIONS ON CACHE BOOL "Use SSE4 instructions")
 # Make DLIB_ASSERT statements not abort the python interpreter, but just return an error.
 add_definitions(-DDLIB_NO_ABORT_ON_2ND_FATAL_ERROR)
 
+# Set this to disable link time optimization. The only reason for
+# doing this to make the compile faster which is nice when developing
+# new modules.
+#set(PYBIND11_LTO_CXX_FLAGS "")
+
 
 # Avoid cmake warnings about changes in behavior of some Mac OS X path 
 # variable we don't care about.