Default include directory for sgif90

[Wayne Vieira <waynev@xxxxxxxxxxxxx>]

Isn't sgif90 supposed to use /usr/include for searching for includes?

I ran the following example test case
     
      program test
      INCLUDE "mpif.h" 
c     USE MPI    #This works, as expected
      INTEGER*8 error
      CALL MPI_INIT(error)
      write(6,*)'hello penguins'
      call MPI_Finalize(error)
      stop
      end

If I have the full path or -I/usr/include it works without error, but
not by default.  What are the default search directories for include
files?

Wayne