make: error out on some more syntax errors

Previously, these errors only produced a message on stderr. They only
affected make's exit status when they were evaluated at parse time, but
not when evaluating the commands for a specific target right before
executing them.

The affected syntax errors are:
* invalid regular expressions in the ':C' modifier
* out-of-range references to regex groups in the ':C' modifier
* unfinished modifiers

make: add detailed exit status to message for failed sub-commands

Several commands communicate via the exit status and not only
distinguish between zero and non-zero, so make this information
available to ease investigations.

The command "false" is not guaranteed to exit with a consistent status,
so use "(exit 13)" instead in the tests, to keep these tests portable
across different operating systems. The exit status 127 is required for
a shell that cannot find a command, so keep that one.

branches: 1.20.2;
make: provide more context information for parse/evaluate errors

tests/make: test the '::=' modifier in target scope

tests/make: finish incomplete sentence in test for assignment modifiers

tests/make: test the '::=' assignment modifier

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.

make: fix mistakes, spelling and typos in comments and manual page

No binary change for -DNDEBUG.

tests/make: make test for '::=' easier to read, fix comments

tests/make: convert tests for modifier '::=' to parse time

This puts the expected result of the expressions closer to the
expressions, making the tests self-contained.

The error messages that used to produce trailing spaces have been fixed
in var.c 1.853 from 2021-02-23. The error message now encloses the
variable name in quotes.

make: fix double varname expansion in the variable modifier '::='

This is an edge case that doesn't occur in practice since pretty much
nobody dares to use variable names that contain an actual '$' in their
name. This is not about the fairly common VAR.${param} (as written in
the makefile), but instead about the variable whose name is literally
'VAR.${param}'.

The test demonstrates that after the fix, the variable name is taken
exactly as-is for the simple assignment modifier '::='. There are no
such tests for the modifiers '::+=', '::!=' and '::?=', but that's ok.
The code in ApplyModifier_Assign would look assymetrical and suspicious
enough if one of these modifiers would expand its variable name and the
others wouldn't.

tests/make: demonstrate that the modifier '::=' expands the varname

make: add test for ::= modifier enclosed in parentheses

make(1): remove outdated comment from test

It was fixed in var.c 1.472 from 2020-08-25.

make(1): add test for the ::+= modifier expanding its right-hand side

make(1): explain existing tests for the ::= assignment modifiers

make(1): fix error message for ::!= modifier with shell error

It's just too easy to confuse st->val and val.

make(1): add test for ::!= modifier with shell error

make(1): move test for the ::= modifier to varmod-assign

make(1): explain the varmod-assign test

I have no idea why I added the mod-assign-nested test. It is completely
boring and doesn't provide any insight.

make(1): move tests for the :gmtime and ::= modifiers to separate files

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: provide more context information for parse/evaluate errors

tests/make: test the '::=' modifier in target scope

tests/make: finish incomplete sentence in test for assignment modifiers

tests/make: test the '::=' assignment modifier

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.

make: fix mistakes, spelling and typos in comments and manual page

No binary change for -DNDEBUG.

tests/make: make test for '::=' easier to read, fix comments

tests/make: convert tests for modifier '::=' to parse time

This puts the expected result of the expressions closer to the
expressions, making the tests self-contained.

The error messages that used to produce trailing spaces have been fixed
in var.c 1.853 from 2021-02-23. The error message now encloses the
variable name in quotes.

make: fix double varname expansion in the variable modifier '::='

This is an edge case that doesn't occur in practice since pretty much
nobody dares to use variable names that contain an actual '$' in their
name. This is not about the fairly common VAR.${param} (as written in
the makefile), but instead about the variable whose name is literally
'VAR.${param}'.

The test demonstrates that after the fix, the variable name is taken
exactly as-is for the simple assignment modifier '::='. There are no
such tests for the modifiers '::+=', '::!=' and '::?=', but that's ok.
The code in ApplyModifier_Assign would look assymetrical and suspicious
enough if one of these modifiers would expand its variable name and the
others wouldn't.

tests/make: demonstrate that the modifier '::=' expands the varname

make: add test for ::= modifier enclosed in parentheses

make(1): remove outdated comment from test

It was fixed in var.c 1.472 from 2020-08-25.

make(1): add test for the ::+= modifier expanding its right-hand side

make(1): explain existing tests for the ::= assignment modifiers

make(1): fix error message for ::!= modifier with shell error

It's just too easy to confuse st->val and val.

make(1): add test for ::!= modifier with shell error

make(1): move test for the ::= modifier to varmod-assign

make(1): explain the varmod-assign test

I have no idea why I added the mod-assign-nested test. It is completely
boring and doesn't provide any insight.

make(1): move tests for the :gmtime and ::= modifiers to separate files

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 the '::=' modifier in target scope

tests/make: finish incomplete sentence in test for assignment modifiers

tests/make: test the '::=' assignment modifier

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.

make: fix mistakes, spelling and typos in comments and manual page

No binary change for -DNDEBUG.

tests/make: make test for '::=' easier to read, fix comments

tests/make: convert tests for modifier '::=' to parse time

This puts the expected result of the expressions closer to the
expressions, making the tests self-contained.

The error messages that used to produce trailing spaces have been fixed
in var.c 1.853 from 2021-02-23. The error message now encloses the
variable name in quotes.

make: fix double varname expansion in the variable modifier '::='

This is an edge case that doesn't occur in practice since pretty much
nobody dares to use variable names that contain an actual '$' in their
name. This is not about the fairly common VAR.${param} (as written in
the makefile), but instead about the variable whose name is literally
'VAR.${param}'.

The test demonstrates that after the fix, the variable name is taken
exactly as-is for the simple assignment modifier '::='. There are no
such tests for the modifiers '::+=', '::!=' and '::?=', but that's ok.
The code in ApplyModifier_Assign would look assymetrical and suspicious
enough if one of these modifiers would expand its variable name and the
others wouldn't.

tests/make: demonstrate that the modifier '::=' expands the varname

make: add test for ::= modifier enclosed in parentheses

make(1): remove outdated comment from test

It was fixed in var.c 1.472 from 2020-08-25.

make(1): add test for the ::+= modifier expanding its right-hand side

make(1): explain existing tests for the ::= assignment modifiers

make(1): fix error message for ::!= modifier with shell error

It's just too easy to confuse st->val and val.

make(1): add test for ::!= modifier with shell error

make(1): move test for the ::= modifier to varmod-assign

make(1): explain the varmod-assign test

I have no idea why I added the mod-assign-nested test. It is completely
boring and doesn't provide any insight.

make(1): move tests for the :gmtime and ::= modifiers to separate files

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: finish incomplete sentence in test for assignment modifiers

tests/make: test the '::=' assignment modifier

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.

make: fix mistakes, spelling and typos in comments and manual page

No binary change for -DNDEBUG.

tests/make: make test for '::=' easier to read, fix comments

tests/make: convert tests for modifier '::=' to parse time

This puts the expected result of the expressions closer to the
expressions, making the tests self-contained.

The error messages that used to produce trailing spaces have been fixed
in var.c 1.853 from 2021-02-23. The error message now encloses the
variable name in quotes.

make: fix double varname expansion in the variable modifier '::='

This is an edge case that doesn't occur in practice since pretty much
nobody dares to use variable names that contain an actual '$' in their
name. This is not about the fairly common VAR.${param} (as written in
the makefile), but instead about the variable whose name is literally
'VAR.${param}'.

The test demonstrates that after the fix, the variable name is taken
exactly as-is for the simple assignment modifier '::='. There are no
such tests for the modifiers '::+=', '::!=' and '::?=', but that's ok.
The code in ApplyModifier_Assign would look assymetrical and suspicious
enough if one of these modifiers would expand its variable name and the
others wouldn't.

tests/make: demonstrate that the modifier '::=' expands the varname

make: add test for ::= modifier enclosed in parentheses

make(1): remove outdated comment from test

It was fixed in var.c 1.472 from 2020-08-25.

make(1): add test for the ::+= modifier expanding its right-hand side

make(1): explain existing tests for the ::= assignment modifiers

make(1): fix error message for ::!= modifier with shell error

It's just too easy to confuse st->val and val.

make(1): add test for ::!= modifier with shell error

make(1): move test for the ::= modifier to varmod-assign

make(1): explain the varmod-assign test

I have no idea why I added the mod-assign-nested test. It is completely
boring and doesn't provide any insight.

make(1): move tests for the :gmtime and ::= modifiers to separate files

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: finish incomplete sentence in test for assignment modifiers

tests/make: test the '::=' assignment modifier

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.

make: fix mistakes, spelling and typos in comments and manual page

No binary change for -DNDEBUG.

tests/make: make test for '::=' easier to read, fix comments

tests/make: convert tests for modifier '::=' to parse time

This puts the expected result of the expressions closer to the
expressions, making the tests self-contained.

The error messages that used to produce trailing spaces have been fixed
in var.c 1.853 from 2021-02-23. The error message now encloses the
variable name in quotes.

make: fix double varname expansion in the variable modifier '::='

This is an edge case that doesn't occur in practice since pretty much
nobody dares to use variable names that contain an actual '$' in their
name. This is not about the fairly common VAR.${param} (as written in
the makefile), but instead about the variable whose name is literally
'VAR.${param}'.

The test demonstrates that after the fix, the variable name is taken
exactly as-is for the simple assignment modifier '::='. There are no
such tests for the modifiers '::+=', '::!=' and '::?=', but that's ok.
The code in ApplyModifier_Assign would look assymetrical and suspicious
enough if one of these modifiers would expand its variable name and the
others wouldn't.

tests/make: demonstrate that the modifier '::=' expands the varname

make: add test for ::= modifier enclosed in parentheses

make(1): remove outdated comment from test

It was fixed in var.c 1.472 from 2020-08-25.

make(1): add test for the ::+= modifier expanding its right-hand side

make(1): explain existing tests for the ::= assignment modifiers

make(1): fix error message for ::!= modifier with shell error

It's just too easy to confuse st->val and val.

make(1): add test for ::!= modifier with shell error

make(1): move test for the ::= modifier to varmod-assign

make(1): explain the varmod-assign test

I have no idea why I added the mod-assign-nested test. It is completely
boring and doesn't provide any insight.

make(1): move tests for the :gmtime and ::= modifiers to separate files

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: 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.

make: fix mistakes, spelling and typos in comments and manual page

No binary change for -DNDEBUG.

tests/make: make test for '::=' easier to read, fix comments

tests/make: convert tests for modifier '::=' to parse time

This puts the expected result of the expressions closer to the
expressions, making the tests self-contained.

The error messages that used to produce trailing spaces have been fixed
in var.c 1.853 from 2021-02-23. The error message now encloses the
variable name in quotes.

make: fix double varname expansion in the variable modifier '::='

This is an edge case that doesn't occur in practice since pretty much
nobody dares to use variable names that contain an actual '$' in their
name. This is not about the fairly common VAR.${param} (as written in
the makefile), but instead about the variable whose name is literally
'VAR.${param}'.

The test demonstrates that after the fix, the variable name is taken
exactly as-is for the simple assignment modifier '::='. There are no
such tests for the modifiers '::+=', '::!=' and '::?=', but that's ok.
The code in ApplyModifier_Assign would look assymetrical and suspicious
enough if one of these modifiers would expand its variable name and the
others wouldn't.

tests/make: demonstrate that the modifier '::=' expands the varname

make: add test for ::= modifier enclosed in parentheses

make(1): remove outdated comment from test

It was fixed in var.c 1.472 from 2020-08-25.

make(1): add test for the ::+= modifier expanding its right-hand side

make(1): explain existing tests for the ::= assignment modifiers

make(1): fix error message for ::!= modifier with shell error

It's just too easy to confuse st->val and val.

make(1): add test for ::!= modifier with shell error

make(1): move test for the ::= modifier to varmod-assign

make(1): explain the varmod-assign test

I have no idea why I added the mod-assign-nested test. It is completely
boring and doesn't provide any insight.

make(1): move tests for the :gmtime and ::= modifiers to separate files

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: fix mistakes, spelling and typos in comments and manual page

No binary change for -DNDEBUG.

tests/make: make test for '::=' easier to read, fix comments

tests/make: convert tests for modifier '::=' to parse time

This puts the expected result of the expressions closer to the
expressions, making the tests self-contained.

The error messages that used to produce trailing spaces have been fixed
in var.c 1.853 from 2021-02-23. The error message now encloses the
variable name in quotes.

make: fix double varname expansion in the variable modifier '::='

This is an edge case that doesn't occur in practice since pretty much
nobody dares to use variable names that contain an actual '$' in their
name. This is not about the fairly common VAR.${param} (as written in
the makefile), but instead about the variable whose name is literally
'VAR.${param}'.

The test demonstrates that after the fix, the variable name is taken
exactly as-is for the simple assignment modifier '::='. There are no
such tests for the modifiers '::+=', '::!=' and '::?=', but that's ok.
The code in ApplyModifier_Assign would look assymetrical and suspicious
enough if one of these modifiers would expand its variable name and the
others wouldn't.

tests/make: demonstrate that the modifier '::=' expands the varname

make: add test for ::= modifier enclosed in parentheses

make(1): remove outdated comment from test

It was fixed in var.c 1.472 from 2020-08-25.

make(1): add test for the ::+= modifier expanding its right-hand side

make(1): explain existing tests for the ::= assignment modifiers

make(1): fix error message for ::!= modifier with shell error

It's just too easy to confuse st->val and val.

make(1): add test for ::!= modifier with shell error

make(1): move test for the ::= modifier to varmod-assign

make(1): explain the varmod-assign test

I have no idea why I added the mod-assign-nested test. It is completely
boring and doesn't provide any insight.

make(1): move tests for the :gmtime and ::= modifiers to separate files

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: make test for '::=' easier to read, fix comments

tests/make: convert tests for modifier '::=' to parse time

This puts the expected result of the expressions closer to the
expressions, making the tests self-contained.

The error messages that used to produce trailing spaces have been fixed
in var.c 1.853 from 2021-02-23. The error message now encloses the
variable name in quotes.

make: fix double varname expansion in the variable modifier '::='

This is an edge case that doesn't occur in practice since pretty much
nobody dares to use variable names that contain an actual '$' in their
name. This is not about the fairly common VAR.${param} (as written in
the makefile), but instead about the variable whose name is literally
'VAR.${param}'.

The test demonstrates that after the fix, the variable name is taken
exactly as-is for the simple assignment modifier '::='. There are no
such tests for the modifiers '::+=', '::!=' and '::?=', but that's ok.
The code in ApplyModifier_Assign would look assymetrical and suspicious
enough if one of these modifiers would expand its variable name and the
others wouldn't.

tests/make: demonstrate that the modifier '::=' expands the varname

make: add test for ::= modifier enclosed in parentheses

make(1): remove outdated comment from test

It was fixed in var.c 1.472 from 2020-08-25.

make(1): add test for the ::+= modifier expanding its right-hand side

make(1): explain existing tests for the ::= assignment modifiers

make(1): fix error message for ::!= modifier with shell error

It's just too easy to confuse st->val and val.

make(1): add test for ::!= modifier with shell error

make(1): move test for the ::= modifier to varmod-assign

make(1): explain the varmod-assign test

I have no idea why I added the mod-assign-nested test. It is completely
boring and doesn't provide any insight.

make(1): move tests for the :gmtime and ::= modifiers to separate files

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: convert tests for modifier '::=' to parse time

This puts the expected result of the expressions closer to the
expressions, making the tests self-contained.

The error messages that used to produce trailing spaces have been fixed
in var.c 1.853 from 2021-02-23. The error message now encloses the
variable name in quotes.

make: fix double varname expansion in the variable modifier '::='

This is an edge case that doesn't occur in practice since pretty much
nobody dares to use variable names that contain an actual '$' in their
name. This is not about the fairly common VAR.${param} (as written in
the makefile), but instead about the variable whose name is literally
'VAR.${param}'.

The test demonstrates that after the fix, the variable name is taken
exactly as-is for the simple assignment modifier '::='. There are no
such tests for the modifiers '::+=', '::!=' and '::?=', but that's ok.
The code in ApplyModifier_Assign would look assymetrical and suspicious
enough if one of these modifiers would expand its variable name and the
others wouldn't.

tests/make: demonstrate that the modifier '::=' expands the varname

make: add test for ::= modifier enclosed in parentheses

make(1): remove outdated comment from test

It was fixed in var.c 1.472 from 2020-08-25.

make(1): add test for the ::+= modifier expanding its right-hand side

make(1): explain existing tests for the ::= assignment modifiers

make(1): fix error message for ::!= modifier with shell error

It's just too easy to confuse st->val and val.

make(1): add test for ::!= modifier with shell error

make(1): move test for the ::= modifier to varmod-assign

make(1): explain the varmod-assign test

I have no idea why I added the mod-assign-nested test. It is completely
boring and doesn't provide any insight.

make(1): move tests for the :gmtime and ::= modifiers to separate files

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: fix double varname expansion in the variable modifier '::='

This is an edge case that doesn't occur in practice since pretty much
nobody dares to use variable names that contain an actual '$' in their
name. This is not about the fairly common VAR.${param} (as written in
the makefile), but instead about the variable whose name is literally
'VAR.${param}'.

The test demonstrates that after the fix, the variable name is taken
exactly as-is for the simple assignment modifier '::='. There are no
such tests for the modifiers '::+=', '::!=' and '::?=', but that's ok.
The code in ApplyModifier_Assign would look assymetrical and suspicious
enough if one of these modifiers would expand its variable name and the
others wouldn't.

tests/make: demonstrate that the modifier '::=' expands the varname

make: add test for ::= modifier enclosed in parentheses

make(1): remove outdated comment from test

It was fixed in var.c 1.472 from 2020-08-25.

make(1): add test for the ::+= modifier expanding its right-hand side

make(1): explain existing tests for the ::= assignment modifiers

make(1): fix error message for ::!= modifier with shell error

It's just too easy to confuse st->val and val.

make(1): add test for ::!= modifier with shell error

make(1): move test for the ::= modifier to varmod-assign

make(1): explain the varmod-assign test

I have no idea why I added the mod-assign-nested test. It is completely
boring and doesn't provide any insight.

make(1): move tests for the :gmtime and ::= modifiers to separate files

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: add test for ::= modifier enclosed in parentheses

make(1): remove outdated comment from test

It was fixed in var.c 1.472 from 2020-08-25.

make(1): add test for the ::+= modifier expanding its right-hand side

make(1): explain existing tests for the ::= assignment modifiers

make(1): fix error message for ::!= modifier with shell error

It's just too easy to confuse st->val and val.

make(1): add test for ::!= modifier with shell error

make(1): move test for the ::= modifier to varmod-assign

make(1): explain the varmod-assign test

I have no idea why I added the mod-assign-nested test. It is completely
boring and doesn't provide any insight.

make(1): move tests for the :gmtime and ::= modifiers to separate files

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): remove outdated comment from test

It was fixed in var.c 1.472 from 2020-08-25.

make(1): add test for the ::+= modifier expanding its right-hand side

make(1): explain existing tests for the ::= assignment modifiers

make(1): fix error message for ::!= modifier with shell error

It's just too easy to confuse st->val and val.

make(1): add test for ::!= modifier with shell error

make(1): move test for the ::= modifier to varmod-assign

make(1): explain the varmod-assign test

I have no idea why I added the mod-assign-nested test. It is completely
boring and doesn't provide any insight.

make(1): move tests for the :gmtime and ::= modifiers to separate files

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.