Hide Informix datatypes. They are not seen by our built process anymore.

src/interfaces/ecpg/ChangeLog

src/interfaces/ecpg/compatlib/informix.c

src/interfaces/ecpg/include/Makefile

src/interfaces/ecpg/include/compatlib.h

src/interfaces/ecpg/include/datetime.h

src/interfaces/ecpg/include/decimal.h

src/interfaces/ecpg/include/ecpg_informix.h

src/interfaces/ecpg/pgtypeslib/interval.c