[m-rev.] trivial diff: don't allow asm_jump.gc.pregen as a boostrap grade

[Julien Fischer]

Don't allow asm_jump.gc.pregen as a bootstrap grade.

configure.ac:
      Don't allow the use of asm_jump.gc.pregen as a bootstrap grade.
      We don't test the asm_jump grade regularly and historically the asm_jump
      grade haven't exactly been reliable.

Julien.

diff --git a/configure.ac b/configure.ac
index 5198a7c..9619319 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3450,16 +3450,16 @@ esac
  # with the C files that we ship in the source distribution.  The C files in the
  # source distribution are generated in hlc.gc.pregen or asm_fast.gc.pregen.
  # In the former case, we _must_ use the grade hlc.gc.pregen, in the latter case
-# we can use any of the base LLDS grades (it's the same C code), except that a
-# couple of them (fast and jump) don't support code addresses in static
-# initalizers.
+# we can, in principle, use any of the base LLDS grades (it's the same C code).
+# We don't use fast and jump as they don't support code addresses in static
+# initializers and we don't use asm_jump as it isn't regularly tested.

  if test "$BOOTSTRAP_HLC" = "yes"
  then
      BOOTSTRAP_GRADE=hlc.gc.pregen
  else
      case $BEST_LLDS_BASE_GRADE in
-        jump|fast)
+        asm_jump|jump|fast)
              if test $mercury_cv_gcc_model_reg = yes; then
                  BOOTSTRAP_GRADE=reg.gc.pregen
              else