[Gm2] more fixes

[Gaius Mulley]

Hi,

the current state of play regarding regression tests on x86_64 is:

# of expected passes            7650
# of unexpected failures        42
# of unresolved testcases       18

the following changes have been made:

    * gm2/gm2-libs/FIO.def:  corrected return type of
      FindPosition to be LONGINT.
    * gm2/gm2-compiler/P2SymBuild.mod:  added procedure
      return type checking between definition and implemention
      modules.
    * gm2/gm2-libs/FIO.def:  FindPosition returns LONGINT.
    * gm2/gm2-libs-pim/FloatingUtilities.mod:  Round
      returns INTEGER and Roundl returns LONGINT.
    * gm2/gm2-libs-pim/FloatingUtilities.def:  Roundl
      also returns LONGINT.

regards,
Gaius