048 Building SGI InventorXt on top of Coin reveals compile-time
    incompabilities.

    A Coin user reported two problems on coin-discuss:

        - InventorXt uses an Inventor-internal include file:
          Inventor/SoDebug.h. This contains a set of static debugging
          helper methods. They seem easy enough to implement, so
          perhaps we should do that.

        - Some explicit inclusion of SbTime.h is needed with Coin,
          that is not necessary with SGI Inventor. This is an
          incompatibility that we would like to get rid of, to make
          porting _other_ code from SGI Inventor to Coin a literal
          no-brainer.

    20021218 mortene.

    UPDATE 20060208 mortene: larsa implemented most of the
    functionality in the SoDebug class. The include issue may still be
    present -- someone needs to try to build SGI InventorXt on top of
    Coin to check.
