[Oberon] Oberon7 - How to get away without FORWARD references

[Andreas Pirklbauer]

   > Refer to Section 2. 'Forward declarations of procedures’ in
   > 'Porting the Oberon Compiler from Oberon to Oberon-07’
   >
   > https://www.inf.ethz.ch/personal/wirth/Oberon/index.html
   >

Alternatively, if you one does have a lot of legacy code containing
many forward references of procedures, you could always decide
to just re-introduce forward declarations of procedures (fully
knowing that this would make the language incompatible).

The implementation cost in the compiler is ~20 source lines of code.

PS: Whether forward declarations of procedures *should* be re-
introduced into the language, could of course be debated.