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: extend test suite, move old tests to 2020 scheme

The tests from envfirst.mk are now in opt-env.mk.
The tests from modword.mk are now in varmod-select-words.mk.

make(1): error out on misspelled .export directives

make(1): error out on misspelled .unexport-env

make(1): fix comment in test for directive unexport-env

make(1): add test for directive unexport-env

make(1): move tests from directives.mk to separate tests

make(1): describe the purpose of each newly added unit test dummy

make(1): add dummies for fine-grained tests, one per single feature

The test names have been derived from the current manual page.

All these tests are dummies right now, and the code from the existing
tests will be moved into the new tests step by step.

This is done to prevent modmisc, escape, varmod-edge and varmisc from
growing without any bounds, and to reduce the side-effects of one test
to the others.

tests/make: extend test suite, move old tests to 2020 scheme

The tests from envfirst.mk are now in opt-env.mk.
The tests from modword.mk are now in varmod-select-words.mk.

make(1): error out on misspelled .export directives

make(1): error out on misspelled .unexport-env

make(1): fix comment in test for directive unexport-env

make(1): add test for directive unexport-env

make(1): move tests from directives.mk to separate tests

make(1): describe the purpose of each newly added unit test dummy

make(1): add dummies for fine-grained tests, one per single feature

The test names have been derived from the current manual page.

All these tests are dummies right now, and the code from the existing
tests will be moved into the new tests step by step.

This is done to prevent modmisc, escape, varmod-edge and varmisc from
growing without any bounds, and to reduce the side-effects of one test
to the others.

make(1): error out on misspelled .export directives

make(1): error out on misspelled .unexport-env

make(1): fix comment in test for directive unexport-env

make(1): add test for directive unexport-env

make(1): move tests from directives.mk to separate tests

make(1): describe the purpose of each newly added unit test dummy

make(1): add dummies for fine-grained tests, one per single feature

The test names have been derived from the current manual page.

All these tests are dummies right now, and the code from the existing
tests will be moved into the new tests step by step.

This is done to prevent modmisc, escape, varmod-edge and varmisc from
growing without any bounds, and to reduce the side-effects of one test
to the others.

make(1): fix comment in test for directive unexport-env

make(1): add test for directive unexport-env

make(1): move tests from directives.mk to separate tests

make(1): describe the purpose of each newly added unit test dummy

make(1): add dummies for fine-grained tests, one per single feature

The test names have been derived from the current manual page.

All these tests are dummies right now, and the code from the existing
tests will be moved into the new tests step by step.

This is done to prevent modmisc, escape, varmod-edge and varmisc from
growing without any bounds, and to reduce the side-effects of one test
to the others.

make(1): move tests from directives.mk to separate tests

make(1): describe the purpose of each newly added unit test dummy

make(1): add dummies for fine-grained tests, one per single feature

The test names have been derived from the current manual page.

All these tests are dummies right now, and the code from the existing
tests will be moved into the new tests step by step.

This is done to prevent modmisc, escape, varmod-edge and varmisc from
growing without any bounds, and to reduce the side-effects of one test
to the others.