This extract from the code of Guglielmo Pasa causes GNU Fortran 95 (GCC 4.1.0 
20050401 (experimental)) to go into an infinite loop.  Reducing the number of 
optional arguments or changing LEN(WHAT) to LEN=10, for example, stop the 
infinite loop.

  SUBROUTINE CQUERY(WHAT,OUI,NON)
    CHARACTER(LEN=*),INTENT(INOUT)       :: WHAT
    CHARACTER(LEN=*),INTENT(IN),OPTIONAL :: OUI,NON
    INTEGER               :: INFO
    CHARACTER(LEN(WHAT))   :: REP,Y0,N0
    
    Y0=OUI
    N0=NON


  END SUBROUTINE CQUERY