The custom directory is an injection point for custom user configurations.
gmock-port.h
The following macros can be defined:
GMOCK_DECLARE_bool_(name)
GMOCK_DECLARE_int32_(name)
GMOCK_DECLARE_string_(name)
GMOCK_DEFINE_bool_(name, default_val, doc)
GMOCK_DEFINE_int32_(name, default_val, doc)
GMOCK_DEFINE_string_(name, default_val, doc)