Building Python with clang and ccache produces about 200 'parentheses-equality' warnings with the message:
    warning: equality comparison with extraneous parentheses [-Wparentheses-equality]

It seems that clang does not recognize that these extraneous parentheses are valid [1] after a macro expansion because the preprocessing is done as a separate stage by ccache.

[1] For example:
With the macros:
    #define Py_TYPE(ob)           (((PyObject*)(ob))->ob_type)
    #define PyLong_CheckExact(op) (Py_TYPE(op) == &PyLong_Type)
The statement:
    if (PyLong_CheckExact(v))
is expanded to:
    if (((((PyObject*)(v))->ob_type) == &PyLong_Type))
and produces the warning with ccache.