In poppler-document.cc:

        g_set_error (error, G_FILE_ERROR,
		     g_file_error_from_errno (fopen_errno),
		     strerror(fopen_errno));

This is wrong; it should use g_strerror. See the g_strerror docs: 

You should use this function in preference to strerror(), because it returns a string in UTF-8 encoding, and since not all platforms support the strerror() function.