Fix CT_SanitizePath

Replace the over-engineered and buggy test in CT_SanitizePath
with a straight forward string pattern match, and also
handle empty PATH elements which are qeuivalent to ".".

Thanks-To: Arnaud Lacombe <lacombar@gmail.com>
Signed-off-by: Johannes Stezenbach <js@sig21.net>

 # Compute M68k-specific values

 CT_DoArchTupleValues() {

     :

 }