Workaround for __qualname__ on PyPy3

Author: isuruf

include/pybind11/detail/class.h

@@ -15,7 +15,7 @@
 NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 NAMESPACE_BEGIN(detail)
 
-#if PY_VERSION_HEX >= 0x03030000
+#if PY_VERSION_HEX >= 0x03030000 && !defined(PYPY_VERSION)
 #  define PYBIND11_BUILTIN_QUALNAME
 #  define PYBIND11_SET_OLDPY_QUALNAME(obj, nameobj)
 #else