make: provide more context information for parse/evaluate errors

tests/make: replace 'variable expression' with 'expression'

Each expression is based on a variable, there's no need for the
verbosity. The wording in make's diagnostics will be changed in a
follow-up commit.

tests/make: force line-based diagnostics to be listed in the tests

This way, contradictions between the intended output and the actual
output are closer together and have a better chance of being spotted.

tests/make: demonstrate use-after-free in modifier ':@'

tests/make: test and document .MAKE.SAVE_DOLLARS and ':='

make: disallow '$' in the variable name of the modifier ':@'

If this restriction should break any existing makefile, the author of
that makefile was probably heading for the IOMCC.

tests/make: split test for modifier ':@' into separate files

The file varmod-loop.mk has grown too large to be single-purpose, plus
it combined parse-time and run-time tests. This has the downside that
as soon as a parse-time test results in an error, the run-time tests are
not run anymore.

tests/make: replace 'variable expression' with 'expression'

Each expression is based on a variable, there's no need for the
verbosity. The wording in make's diagnostics will be changed in a
follow-up commit.

tests/make: force line-based diagnostics to be listed in the tests

This way, contradictions between the intended output and the actual
output are closer together and have a better chance of being spotted.

tests/make: demonstrate use-after-free in modifier ':@'

tests/make: test and document .MAKE.SAVE_DOLLARS and ':='

make: disallow '$' in the variable name of the modifier ':@'

If this restriction should break any existing makefile, the author of
that makefile was probably heading for the IOMCC.

tests/make: split test for modifier ':@' into separate files

The file varmod-loop.mk has grown too large to be single-purpose, plus
it combined parse-time and run-time tests. This has the downside that
as soon as a parse-time test results in an error, the run-time tests are
not run anymore.

tests/make: force line-based diagnostics to be listed in the tests

This way, contradictions between the intended output and the actual
output are closer together and have a better chance of being spotted.

tests/make: demonstrate use-after-free in modifier ':@'

tests/make: test and document .MAKE.SAVE_DOLLARS and ':='

make: disallow '$' in the variable name of the modifier ':@'

If this restriction should break any existing makefile, the author of
that makefile was probably heading for the IOMCC.

tests/make: split test for modifier ':@' into separate files

The file varmod-loop.mk has grown too large to be single-purpose, plus
it combined parse-time and run-time tests. This has the downside that
as soon as a parse-time test results in an error, the run-time tests are
not run anymore.

tests/make: demonstrate use-after-free in modifier ':@'

tests/make: test and document .MAKE.SAVE_DOLLARS and ':='

make: disallow '$' in the variable name of the modifier ':@'

If this restriction should break any existing makefile, the author of
that makefile was probably heading for the IOMCC.

tests/make: split test for modifier ':@' into separate files

The file varmod-loop.mk has grown too large to be single-purpose, plus
it combined parse-time and run-time tests. This has the downside that
as soon as a parse-time test results in an error, the run-time tests are
not run anymore.

tests/make: test and document .MAKE.SAVE_DOLLARS and ':='

make: disallow '$' in the variable name of the modifier ':@'

If this restriction should break any existing makefile, the author of
that makefile was probably heading for the IOMCC.

tests/make: split test for modifier ':@' into separate files

The file varmod-loop.mk has grown too large to be single-purpose, plus
it combined parse-time and run-time tests. This has the downside that
as soon as a parse-time test results in an error, the run-time tests are
not run anymore.