[m-dev.] Test failures in rotd-2021-07-31 due to missing .mh files

[Julien Fischer]

Hi,

There have been some new test failures with rotd-2021-07-31 due to 
missing .mh files, specifically:

      valid/bug486
      valid_seq/exported_foreign_type
      valid_seq/test_xmlreader

This appear to be due to one of the recent changes to how dependencies
are handled.  Here is a diff between the versions of bug486.d generated
by rotd-2021-07-30 (old) and rotds-2021-07-31 (new) respectively

--- bug486.d-old        2021-07-31 23:38:48.275318815 +1000
+++ bug486.d-new        2021-07-31 23:38:24.776331775 +1000
@@ -2,7 +2,7 @@

   # Automatically generated module dependencies for
   # module `bug486' in source file `bug486.m'.
-# Generated by Mercury compiler version rotd-2021-07-30
+# Generated by Mercury compiler version rotd-2021-07-31
   # configured for x86_64-pc-linux-gnu.

   # RULE trans_opt_deps
@@ -69,20 +69,6 @@
                  private_builtin.int3 \
                  bug486.window.int3

-# RULE foreign_deps_for_.mh
-bug486.$O : \
-               bug486.mh \
-               builtin.mh \
-               private_builtin.mh \
-               bug486.window.mh
-
-# RULE foreign_deps_for_.mh
-bug486.pic_o : \
-               bug486.mh \
-               builtin.mh \
-               private_builtin.mh \
-               bug486.window.mh
-
   # RULE int0_on_date0
   bug486.int0 : bug486.date0
          @:

I would note that this problem also affects the compiler when built with
a sufficiently large number of parallel jobs (e.g. -j8).

Julien.