GeezerVison

Can you make this a generic function instead? it's useful for checking the presence of a macro. Make the includes and the expected macro type parameters of that function, as well as the name of your HAVE_ macro as you did. This could be useful elsewhere.

Ina ddition, there is no need for the return 0; as it's implicit. Also remove `/* Test whether $1 is declared */ because it's trivial what it does.

Thanks for the feedback @picnixz. Actually such a generic macro already "exists" to some degree, it's AC_CHECK_DECL. However, we can't use it in our specific case because what AC_CHECK_DECL does is:

#ifndef YOUR_DECLARATION
(void) YOUR_DECLARATION;
#endif 

The idea being: the #ifndef test if it is a macro => if it is, then fine, we're good. If it's not a macro, it checks if it's a valid r-value.

In our case, TCGETA is a macro, BUT we need to check that it is actually usable, not just "defined". And that's why AC_CHECK_DECL doesn't do the trick.

If you still think a generic macro would be good, what name should it have? Indeed, PY_CHECK_DECL would be very confusing if it has this subtle difference with AC_CHECK_DECL. Or maybe PY_CHECK_USABLE_DECL ?

And of course, our macro isn't as generic as AC_CHECK_DECL, because if the declaration exists but has no value (like #define FOO), then our test will fail.

My idea was actually different. What I wanted to test is:

TYPE holder = $1;

where you specify TYPE (in your case it's long). And for the name, it would be PY_CHECK_CONSTANT. I wanted you to actually remove the comment but not the test itself.

Makes a lot of sense, will do!

Why is the NEWS entry still long? I think you overwrote your change.

(Sorry, but I really want to avoid vertically expanding our configure.ac as much as possible; ideally we should have all "functions" in a separate file but we don't do that...)