* path.cc (path_conv::check): Add signal protection here since retrieving info
about remote shares can take some time.
* path.h (check_null_empty_str_errno): Convert to a function prototype.
* path.cc (check_null_empty_str): Move to miscfuncs.cc.
* miscfuncs.cc (check_null_empty_str_errno): New function.
(__check_null_invalid_struct): Ditto.
(__check_null_invalid_struct_errno): Ditto.
(check_null_empty_str): Change from VirtualQuery to IsBadWritePtr.
* thread.cc (check_valid_pointer): Ditto.
* resource.cc (getrlimit): Use check_null_invalid_struct macro for checking
validity of pointer.
(setrlimit): Ditto.
