[gentoo-pms] EAPI 8 draft for review

[Ulrich Müller]

Here is the series of EAPI 8 patches for review. They include the
pre-approved items from the 2020-11-08 Council meeting, with two
modifications:

- "Empty working directory in pkg_* phase functions" added
- "Variant of || ( ) with defined runtime behaviour" dropped,
  because the implementation is not ready

The complete list of features is:

- Less strict naming rules for files in updates directory
- Bash version is 5.0
- Selective fetch/mirror restriction
- IDEPEND
- Empty working directory in pkg_* phase functions
- Different src_prepare implementation
- PROPERTIES and RESTRICT accumulated across eclasses
- useq banned
- hasv and hasq banned
- econf adds --datarootdir
- econf adds --disable-static
- dosym can create relative paths
- insopts no longer affects doconfd, doenvd and doheader
- exeopts no longer affects doinitd
- usev supports an optional second argument
- unpack no longer supports .7z, .rar, .lha

The rendered version of the spec can be found:
PDF:  https://dev.gentoo.org/~ulm/pms/8-draft/pms.pdf
HTML: https://dev.gentoo.org/~ulm/pms/8-draft/pms.html

Status of implementation in Portage and Pkgcore can be traced here:
https://wiki.gentoo.org/wiki/Future_EAPI/EAPI_8_tentative_features

Thanks to Michał Górny for contributing patches for some of the more
complicated features.

Ulrich