[SV 63098] Temporarily revert the change to pattern rule behavior

The fix for SV 12078 caused a backward-compatibility issue with some
makefiles.  In order to allow users to resolve this issue, revert
that change for this release cycle: it will be reinstated in the
next release cycle.  Introduce a warning if we detect that the recipe
of a multi-target pattern rule doesn't create all the targets.

* NEWS: Announce the future backward-incompatibility.
* doc/make.texi (Pattern Intro): Describe the behavior and that it
will change in the future.
* src/remake.c (check_also_make): Check for also_make targets that
were not created and generate a warning.
(update_goal_chain): Call the new function.
(check_dep): Ditto.
(update_file_1): Defer implicit rule detection until after we check
all the also_make files (as it used to be).
* tests/scripts/features/patternrules: Add tests of the new warning.
Skip the tests for SV 12078.

1 files changed, 16 insertions, 6 deletions

diff --git a/NEWS b/NEWS
index f53e7691..2beec358 100644
--- a/NEWS
+++ b/NEWS
@@ -22,6 +22,16 @@ https://sv.gnu.org/bugs/index.php?group=make&report_id=111&fix_release_id=109&se
   In the NEXT release of GNU make, support for these systems will be removed.
   If you want to see them continue to be supported, contact <bug-make@gnu.org>.
 
+* WARNING: Future backward-incompatibility!
+  In the NEXT release of GNU make, pattern rules will implement the same
+  behavior change for multiple targets as explicit grouped targets, below: if
+  any target of the rule is needed by the build, the recipe will be invoked if
+  any target of the rule is missing or out of date.  During testing some
+  makefiles were found to contain pattern rules that do not build all targets;
+  this can cause issues so we are delaying this change for one release cycle
+  to allow these makefiles to be updated.  GNU make show a warning if it
+  detects this situation: "pattern recipe did not update peer target".
+
 * WARNING: Backward-incompatibility!
   GNU make now uses temporary files in more situations than previous releases.
   If your build system sets TMPDIR (or TMP or TEMP on Windows) and deletes the
@@ -32,12 +42,12 @@ https://sv.gnu.org/bugs/index.php?group=make&report_id=111&fix_release_id=109&se
   needs to find its temporary directory before the makefiles are parsed.
 
 * WARNING: Backward-incompatibility!
-  Previously each target in a grouped target rule (pattern or explicit) was
-  considered individually: if the targets needed by the build were not out of
-  date the recipe was not run even if other targets in the group were out of
-  date.  Now if any of the grouped targets are needed by the build, then if
-  any of the grouped targets are out of date the recipe is run and all targets
-  in the group are considered updated.
+  Previously each target in a explicit grouped target rule was considered
+  individually: if the targets needed by the build were not out of date the
+  recipe was not run even if other targets in the group were out of date.  Now
+  if any of the grouped targets are needed by the build, then if any of the
+  grouped targets are out of date the recipe is run and all targets in the
+  group are considered updated.
 
 * WARNING: Backward-incompatibility!
   Previously if --no-print-directory was seen anywhere in the environment or