make: reduce line length in error messages

The error messages for deeply nested parse errors were hard to decipher,
due to the large amount of text. Split these messages into individual
lines, just as in the backtrace for .include files and .for loops. This
unified backtrace makes the output more uniform.

make: fix exit status for error in .BEGIN/.END prerequisite

tests/make: demonstrate wrong exit status for .END dependency

make: don't run erroneous commands in parallel mode

tests/make: demonstrate failing dependency in parallel mode

In parallel mode, when generating the commands for a target, parse or
evaluation errors still continue generating and executing the commands.
And if the commands succeed, the targets that depend on this target are
still made.

make: error out on parse/evaluation errors in shell commands

The expression ${VAR:X} has an unknown modifier ':X'. Previously, this
expression errored out when the expression was evaluated at parse time,
but not when the expression was evaluated when generating the commands
to bring a target up to date. The errors were previously reported, they
didn't affect the exit status, though.

Now, errors in expressions are handled in the same way, regardless of
the time at which they are evaluated.

make: error out on unclosed expressions during parse time

In exchange, this adds location information.

For unnamed expressions, the value is no longer printed. This will be
added back in a follow-up commit.

tests/make: add expected messages for "Unclosed expression"

make: add more context information to error messages

In case of a parse error or evaluation error, print the variable value
in addition to the variable name, to see the effects of previous
expression modifiers.

In nested make calls, print the current directory at the bottom of a
stack trace, as that information is otherwise hard to get in a parallel
build spanning multiple directories.

make: clean up comments, code and tests

make: provide more context information for parse/evaluate errors

tests/make: reduce trailing whitespace

make(1): add test for expansion errors in jobs mode

Since compat mode and jobs mode are implemented separately and vary in
lots of small details, each of them needs to be tested on its own.

make: fix exit status for error in .BEGIN/.END prerequisite

tests/make: demonstrate wrong exit status for .END dependency

make: don't run erroneous commands in parallel mode

tests/make: demonstrate failing dependency in parallel mode

In parallel mode, when generating the commands for a target, parse or
evaluation errors still continue generating and executing the commands.
And if the commands succeed, the targets that depend on this target are
still made.

make: error out on parse/evaluation errors in shell commands

The expression ${VAR:X} has an unknown modifier ':X'. Previously, this
expression errored out when the expression was evaluated at parse time,
but not when the expression was evaluated when generating the commands
to bring a target up to date. The errors were previously reported, they
didn't affect the exit status, though.

Now, errors in expressions are handled in the same way, regardless of
the time at which they are evaluated.

make: error out on unclosed expressions during parse time

In exchange, this adds location information.

For unnamed expressions, the value is no longer printed. This will be
added back in a follow-up commit.

tests/make: add expected messages for "Unclosed expression"

make: add more context information to error messages

In case of a parse error or evaluation error, print the variable value
in addition to the variable name, to see the effects of previous
expression modifiers.

In nested make calls, print the current directory at the bottom of a
stack trace, as that information is otherwise hard to get in a parallel
build spanning multiple directories.

make: clean up comments, code and tests

make: provide more context information for parse/evaluate errors

tests/make: reduce trailing whitespace

make(1): add test for expansion errors in jobs mode

Since compat mode and jobs mode are implemented separately and vary in
lots of small details, each of them needs to be tested on its own.

make: don't run erroneous commands in parallel mode

tests/make: demonstrate failing dependency in parallel mode

In parallel mode, when generating the commands for a target, parse or
evaluation errors still continue generating and executing the commands.
And if the commands succeed, the targets that depend on this target are
still made.

make: error out on parse/evaluation errors in shell commands

The expression ${VAR:X} has an unknown modifier ':X'. Previously, this
expression errored out when the expression was evaluated at parse time,
but not when the expression was evaluated when generating the commands
to bring a target up to date. The errors were previously reported, they
didn't affect the exit status, though.

Now, errors in expressions are handled in the same way, regardless of
the time at which they are evaluated.

make: error out on unclosed expressions during parse time

In exchange, this adds location information.

For unnamed expressions, the value is no longer printed. This will be
added back in a follow-up commit.

tests/make: add expected messages for "Unclosed expression"

make: add more context information to error messages

In case of a parse error or evaluation error, print the variable value
in addition to the variable name, to see the effects of previous
expression modifiers.

In nested make calls, print the current directory at the bottom of a
stack trace, as that information is otherwise hard to get in a parallel
build spanning multiple directories.

make: clean up comments, code and tests

make: provide more context information for parse/evaluate errors

tests/make: reduce trailing whitespace

make(1): add test for expansion errors in jobs mode

Since compat mode and jobs mode are implemented separately and vary in
lots of small details, each of them needs to be tested on its own.

make: error out on parse/evaluation errors in shell commands

The expression ${VAR:X} has an unknown modifier ':X'. Previously, this
expression errored out when the expression was evaluated at parse time,
but not when the expression was evaluated when generating the commands
to bring a target up to date. The errors were previously reported, they
didn't affect the exit status, though.

Now, errors in expressions are handled in the same way, regardless of
the time at which they are evaluated.

make: error out on unclosed expressions during parse time

In exchange, this adds location information.

For unnamed expressions, the value is no longer printed. This will be
added back in a follow-up commit.

tests/make: add expected messages for "Unclosed expression"

make: add more context information to error messages

In case of a parse error or evaluation error, print the variable value
in addition to the variable name, to see the effects of previous
expression modifiers.

In nested make calls, print the current directory at the bottom of a
stack trace, as that information is otherwise hard to get in a parallel
build spanning multiple directories.

make: clean up comments, code and tests

make: provide more context information for parse/evaluate errors

tests/make: reduce trailing whitespace

make(1): add test for expansion errors in jobs mode

Since compat mode and jobs mode are implemented separately and vary in
lots of small details, each of them needs to be tested on its own.

make: error out on unclosed expressions during parse time

In exchange, this adds location information.

For unnamed expressions, the value is no longer printed. This will be
added back in a follow-up commit.

tests/make: add expected messages for "Unclosed expression"

make: add more context information to error messages

In case of a parse error or evaluation error, print the variable value
in addition to the variable name, to see the effects of previous
expression modifiers.

In nested make calls, print the current directory at the bottom of a
stack trace, as that information is otherwise hard to get in a parallel
build spanning multiple directories.

make: clean up comments, code and tests

make: provide more context information for parse/evaluate errors

tests/make: reduce trailing whitespace

make(1): add test for expansion errors in jobs mode

Since compat mode and jobs mode are implemented separately and vary in
lots of small details, each of them needs to be tested on its own.

make: error out on unclosed expressions during parse time

In exchange, this adds location information.

For unnamed expressions, the value is no longer printed. This will be
added back in a follow-up commit.

tests/make: add expected messages for "Unclosed expression"

make: add more context information to error messages

In case of a parse error or evaluation error, print the variable value
in addition to the variable name, to see the effects of previous
expression modifiers.

In nested make calls, print the current directory at the bottom of a
stack trace, as that information is otherwise hard to get in a parallel
build spanning multiple directories.

make: clean up comments, code and tests

make: provide more context information for parse/evaluate errors

tests/make: reduce trailing whitespace

make(1): add test for expansion errors in jobs mode

Since compat mode and jobs mode are implemented separately and vary in
lots of small details, each of them needs to be tested on its own.

make: clean up comments, code and tests

make: provide more context information for parse/evaluate errors

tests/make: reduce trailing whitespace

make(1): add test for expansion errors in jobs mode

Since compat mode and jobs mode are implemented separately and vary in
lots of small details, each of them needs to be tested on its own.

make: provide more context information for parse/evaluate errors

tests/make: reduce trailing whitespace

make(1): add test for expansion errors in jobs mode

Since compat mode and jobs mode are implemented separately and vary in
lots of small details, each of them needs to be tested on its own.

tests/make: reduce trailing whitespace

make(1): add test for expansion errors in jobs mode

Since compat mode and jobs mode are implemented separately and vary in
lots of small details, each of them needs to be tested on its own.

make(1): add test for expansion errors in jobs mode

Since compat mode and jobs mode are implemented separately and vary in
lots of small details, each of them needs to be tested on its own.