* ppudump: 
  - Check PPU version to be the same as the current PPU version of the compiler. It prevents reading errors if wrong a unit has wrong PPU version. The version check can be turned off using -S switch.
  - User WriteError() in appropriate places in the code.
  

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@24408 3ad0048d-3df7-0310-abae-a5850022a9f2