Fix for the 0xA0 character problem in the InnoDB FOREIGN KEY parser: if my_isspace() treats 0xA0 as space, then let InnoDB do the same; this might break some multi-byte charset id's, though for big5, ujis, sjis this seems not to change the current behavior (I checked the tables in /share/charsets); this fix must NOT be merged to 4.1 because in 4.1 everything is in UTF-8