tests/lint: make 'expect+-' comments stricter

Previously, the expectations from these comments were already satisfied
if the expectation occurred somewhere in the actual message from lint.
This meant that the prefix 'error:' or 'warning:' could be omitted from
the 'expect' comment. These omissions were hard to see in a manual
review. Now any omissions must be visually marked with '...'.

The test msg_342 now reports its messages properly as being in the file
msg_342.c, rather than msg_341.c. This had been a copy-and-paste
mistake.

tests/lint: add tests for several messages

lint: quote placeholders in messages for unused variables

lint: only define GCC builtins if -g is given

This removes 7 wrong warnings when running lint in -t mode.

Surprisingly, this added a warning that had not been there before in
msg_189.c. This is because check_variable_usage skips the checks when
an error occurred before. All diagnostics that happened were warnings,
but the -w option treats them as errors, see vwarning.

lint: remove message 189, add tests for a few other messages

Message 189 would have applied to traditional C and was supposed to
detect assignments between struct and union types. The corresponding
check had never been implemented though.

Traditional C has been superseded for 30 years now, therefore there is no
point in adding this check retroactively.

lint: add a test for each message produced by lint1

Having a test for each message ensures that upcoming refactorings don't
break the basic functionality. Adding the tests will also discover
previously unknown bugs in lint.

The tests ensure that every lint message can actually be triggered, and
they demonstrate how to do so. Having a separate file for each test
leaves enough space for documenting historical anecdotes, rationale or
edge cases, keeping them away from the source code.

The interesting details of this commit are in Makefile and
t_integration.sh. All other files are just auto-generated.

When running the tests as part of ATF, they are packed together as a
single test case. Conceptually, it would have been better to have each
test as a separate test case, but ATF quickly becomes very slow as soon
as a test program defines too many test cases, and 50 is already too
many. The time complexity is O(n^2), not O(n) as one would expect.
It's the same problem as in tests/usr.bin/make, which has over 300 test
cases as well.

tests/lint: add tests for several messages

lint: quote placeholders in messages for unused variables

lint: only define GCC builtins if -g is given

This removes 7 wrong warnings when running lint in -t mode.

Surprisingly, this added a warning that had not been there before in
msg_189.c. This is because check_variable_usage skips the checks when
an error occurred before. All diagnostics that happened were warnings,
but the -w option treats them as errors, see vwarning.

lint: remove message 189, add tests for a few other messages

Message 189 would have applied to traditional C and was supposed to
detect assignments between struct and union types. The corresponding
check had never been implemented though.

Traditional C has been superseded for 30 years now, therefore there is no
point in adding this check retroactively.

lint: add a test for each message produced by lint1

Having a test for each message ensures that upcoming refactorings don't
break the basic functionality. Adding the tests will also discover
previously unknown bugs in lint.

The tests ensure that every lint message can actually be triggered, and
they demonstrate how to do so. Having a separate file for each test
leaves enough space for documenting historical anecdotes, rationale or
edge cases, keeping them away from the source code.

The interesting details of this commit are in Makefile and
t_integration.sh. All other files are just auto-generated.

When running the tests as part of ATF, they are packed together as a
single test case. Conceptually, it would have been better to have each
test as a separate test case, but ATF quickly becomes very slow as soon
as a test program defines too many test cases, and 50 is already too
many. The time complexity is O(n^2), not O(n) as one would expect.
It's the same problem as in tests/usr.bin/make, which has over 300 test
cases as well.

lint: quote placeholders in messages for unused variables

lint: only define GCC builtins if -g is given

This removes 7 wrong warnings when running lint in -t mode.

Surprisingly, this added a warning that had not been there before in
msg_189.c. This is because check_variable_usage skips the checks when
an error occurred before. All diagnostics that happened were warnings,
but the -w option treats them as errors, see vwarning.

lint: remove message 189, add tests for a few other messages

Message 189 would have applied to traditional C and was supposed to
detect assignments between struct and union types. The corresponding
check had never been implemented though.

Traditional C has been superseded for 30 years now, therefore there is no
point in adding this check retroactively.

lint: add a test for each message produced by lint1

Having a test for each message ensures that upcoming refactorings don't
break the basic functionality. Adding the tests will also discover
previously unknown bugs in lint.

The tests ensure that every lint message can actually be triggered, and
they demonstrate how to do so. Having a separate file for each test
leaves enough space for documenting historical anecdotes, rationale or
edge cases, keeping them away from the source code.

The interesting details of this commit are in Makefile and
t_integration.sh. All other files are just auto-generated.

When running the tests as part of ATF, they are packed together as a
single test case. Conceptually, it would have been better to have each
test as a separate test case, but ATF quickly becomes very slow as soon
as a test program defines too many test cases, and 50 is already too
many. The time complexity is O(n^2), not O(n) as one would expect.
It's the same problem as in tests/usr.bin/make, which has over 300 test
cases as well.

lint: only define GCC builtins if -g is given

This removes 7 wrong warnings when running lint in -t mode.

Surprisingly, this added a warning that had not been there before in
msg_189.c. This is because check_variable_usage skips the checks when
an error occurred before. All diagnostics that happened were warnings,
but the -w option treats them as errors, see vwarning.

lint: remove message 189, add tests for a few other messages

Message 189 would have applied to traditional C and was supposed to
detect assignments between struct and union types. The corresponding
check had never been implemented though.

Traditional C has been superseded for 30 years now, therefore there is no
point in adding this check retroactively.

lint: add a test for each message produced by lint1

Having a test for each message ensures that upcoming refactorings don't
break the basic functionality. Adding the tests will also discover
previously unknown bugs in lint.

The tests ensure that every lint message can actually be triggered, and
they demonstrate how to do so. Having a separate file for each test
leaves enough space for documenting historical anecdotes, rationale or
edge cases, keeping them away from the source code.

The interesting details of this commit are in Makefile and
t_integration.sh. All other files are just auto-generated.

When running the tests as part of ATF, they are packed together as a
single test case. Conceptually, it would have been better to have each
test as a separate test case, but ATF quickly becomes very slow as soon
as a test program defines too many test cases, and 50 is already too
many. The time complexity is O(n^2), not O(n) as one would expect.
It's the same problem as in tests/usr.bin/make, which has over 300 test
cases as well.