I ran into an error like this and perhaps I have a clue was why some people run into it.  Dynamic modules built from Modules/Setup will need to have  -DPy_BUILD_CORE defined within the Setup file in the case they need to use the _Py_BEGIN_SUPPRESS_IPH macro.

The Setup file is generated on figure 'configure' but it is not removed if you run "make clean".  So, if it gets generated without the Py_BUILD_CORE flags in it, you will get this mysterious build error.

Perhaps Modules/makesetup should be intelligent and add the Py_BUILD_CORE flags as needed.  One idea is to check the path of the source code (e.g. timemodule.c) and if the source is within the code interpreter folder,  add the BUILD_CORE flag.

Not sure about other platform build systems.  It looks like PCbuild does something different as it doesn't use makesetup.