Apologies for missing your reply.

To clarify: the patches I linked to fix the build problem. You do not need to run macOS to test them. The failure should be reproducible with a recent version of Clang, or by setting `-Werror=implicit-function-déclaration`.

Hi Alexander,

There is a patch linked in the original report:

https://github.com/macports/macports-ports/commit/38df2ef467d4bcce657e8b8d36735c1fc9bb64eb

It's applied to version 4.8.0. You can find the raw patches here:

https://raw.githubusercontent.com/macports/macports-ports/38df2ef467d4bcce657e8b8d36735c1fc9bb64eb/sysutils/screen/files/patch-configure_no_implicit_defs.diff

https://raw.githubusercontent.com/macports/macports-ports/master/sysutils/screen/files/patch-xcode-12-implicit-function-fixes.diff

MacPorts also apply some additional patches you might be interested in:

https://github.com/macports/macports-ports/tree/38df2ef467d4bcce657e8b8d36735c1fc9bb64eb/sysutils/screen/files

Hi,

I'm a maintainer of Homebrew (a macOS package manager) and we're trying to build packages on the newly released macOS 11.0 and its counterpart Xcode 12 release. GNU Screen v4.8.0 fails to build:

```
configure: checking select with  -lnet -lnsl...
configure: error: !!! no select - no screen
```

and later

```
configure: error: !!! no tgetent - no screen
```

Upon investigation, it seems like it fails because Clang 12 requires functions to be defined before use.

There exist some patches elsewhere that fix this by `include`ing the right headers, for example, this set from MacPorts: https://github.com/macports/macports-ports/commit/38df2ef467d4bcce657e8b8d36735c1fc9bb64eb.

Thanks,

Issy.