GitLab

  Moved template for swis.h out of asm source into separate text file.
Detail:
  s.makehswis: The text which forms the common header for the derived
    swis.h is now stored externally rather than declared inline with
    assembler directives.
  h.swisheaders: The external file containing the common header.
    Now wraps the declarations of _swi and _swix with "#pragma -v4"
    to activate the _swi/_swix parameter checking for those functions.
  Makefile: Added dependency of derived.swis on h.swisheader
Admin:
  Built and exported.  Tested with cc 5.09 and it was happy with the
  new pragma (it ignores it).  Tested with what will be cc 5.10 and
  it recognised it and started checking _swi and _swix calls.

Version 4.90. Tagged as 'RISC_OSLib-4_90'