do coverage test without install lcov

Hi, hackers

In [1] wrote:

> If you don't have lcov or prefer text output over an HTML report, you can also run
> make coverage

[1] https://www.postgresql.org/docs/13/regress-coverage.html

It seems the lcov is not a necessary program to run a coverage test.

But when I configure with --enable-coverage, then error was reported:
        checking for lcov... no
        configure: error: lcov not found

Because it's a little difficult to install lcov in offline environment and we can get a
text format result by running make coverage. How about change this action, when
there is no lcov in system, only a warning message is reported.

The patch attached. Thought ?

Best regards
Shenhao Wang

"[hidden email]" <[hidden email]> writes:
> Because it's a little difficult to install lcov in offline environment and we can get a
> text format result by running make coverage. How about change this action, when
> there is no lcov in system, only a warning message is reported.

> The patch attached. Thought ?

This should use the "missing" mechanism that's already used for,
e.g., flex and bison.

                        regards, tom lane