tests/make: require all expected messages to be listed in the .mk files

make: add .export-all

An explicit syntax for exporting all global variables is much safer
than allowing .export with no argument to do the same.

Add .export-all and have .export with no argument throw a warning saying
to use .export-all

Reviewed by: rillig

tests/make: test and explain exporting of variables

tests/make: show a difference between 'export' and '.export'

make(1): error out on misspelled directives

Before, make accepted misspellings like .warnings, .export-literally and
a few others, all of which are unlikely to occur in practice. See the
test directive-misspellings.mk for further details.

make(1): extract ExportVars from Var_Export

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

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: test and explain exporting of variables

tests/make: show a difference between 'export' and '.export'

make(1): error out on misspelled directives

Before, make accepted misspellings like .warnings, .export-literally and
a few others, all of which are unlikely to occur in practice. See the
test directive-misspellings.mk for further details.

make(1): extract ExportVars from Var_Export

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

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: show a difference between 'export' and '.export'

make(1): error out on misspelled directives

Before, make accepted misspellings like .warnings, .export-literally and
a few others, all of which are unlikely to occur in practice. See the
test directive-misspellings.mk for further details.

make(1): extract ExportVars from Var_Export

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

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 directives

Before, make accepted misspellings like .warnings, .export-literally and
a few others, all of which are unlikely to occur in practice. See the
test directive-misspellings.mk for further details.

make(1): extract ExportVars from Var_Export

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

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): 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): 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.