This reverts commit 6264deece3.
Further investigation discovers that the real issue is that
GNU Emacs compile mode doesn't have a matching regex for GNU
make error messages generated when targets fail. I submitted
a patch to GNU Emacs adding a matcher for compile mode.
Ensure we properly reduce job_slots_used if a command fails because
it doesn't exist/can't be started.
* src/job.h (struct child): Add a field jobslot to be set when using
a job slot.
* src/job.c (start_waiting_job): Remember if we are using a job slot.
(reap_children): Reduce number of job slots used by jobslot.
* src/function.c (func_shell_base): Use error() instead of recreating
the error output.
* src/job.c (exec_command): Show more standard error messages.
* src/load.c (unload_file): Fix whitespace in the error message.
* tests/scripts/features/errors: Add tests for starting non-
existent commands and new error message formats.
* tests/scripts/features/output-sync: New error message formats.
* tests/scripts/functions/shell: Ditto.
While displaying line numbers, show the relevant line number inside
the recipe not just the first line of the entire recipe.
Sample changes suggested by Brian Vandenberg <phantall@gmail.com>
* gnumake.h (gmk_floc): Add an 'offset' to track the recipe offset.
* read.c (eval, eval_makefile, eval_buffer): Initialize 'offset'.
(record_files, install_pattern_rule): Ditto.
* job.c (new_job, job_next_command): Update 'offset' based on the
line of the recipe we're expanding or invoking.
(child_error): Add 'offset' when showing the line number.
* function.c (func_shell_base): Ditto.
* output.c (error, fatal): Ditto.
* NEWS: Mention the new ability.
* tests/scripts/features/errors: Check the line number on errors.
* tests/scripts/functions/warning: Check the line number on warnings.
* tests/scripts/features/output-sync,
tests/scripts/features/parallelism, tests/scripts/functions/shell,
tests/scripts/functions/error: Update line numbers.
