The INCLUDE= directive is optional and has the following
      properties

      1. The time and date stamps of all files placed in the INCLUDE=
         directives will be compared to the time and date stamps of all
         of the objects.

      2. Any object older than any file in the INCLUDE= directive will
         be recompiled.

       PBMake does not check to see if the source file contains an 
       actual reference to the include file. 

      The assumption is that ALL source depend on the INCLUDE=
      directives.

      Any file referenced in a INCLUDE= directive that does not exist as
      an actual file will stop the make process with an appropriate
      error.

      You can override the master INCLUDE= directive by using numbered
      versions for each section. For example, you can:

      INCLUDE= SOMETHIN.CH
      SRCEXT=.PRG

      INCLUDE3= mystuff.h
      SRCEXT3=.C