FIO_PUNIT - Release a unit number

Description:

Give back a Fortran unit number to FIO.

Invocation:

CALL FIO_PUNIT( UNIT, STATUS )

Arguments:

UNIT = INTEGER (Given)

Variable containing the unit number.

STATUS = INTEGER (Given and Returned)

The global status.

Notes:

If STATUS is not set to SAI__OK on input, then the routine will still attempt to execute, but will return with STATUS set to the import value.