Prefix/Darwin

Prefix/Darwin brings the power of Gentoo to Darwin (macOS/OS X) based systems, similar to pkgsrc, macports, and homebrew.

General

macOS follows the normal bootstrap procedure
- Project:Prefix/Bootstrap#Bootstrapping_Prefix
Bootstraps currently done via GCC (DARWIN_USE_GCC=1 is set by default)
- host/Apple Clang from xcode tools is used then GCC is built as soon as possible
- Using GCC as the "system" compiler within Prefix has problems
  - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90709 (general tracker for macOS header/frameworks issues with GCC)
  - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78352 (Blocks support)
    - As a result, can't build things using e.g. Aqua (nice GUI) integrations or other Frameworks (e.g. git keychain integration).
- We use the system (host) linker because we can't build Apple's linker independently within our prefix without Clang, because it uses Blocks
Possibility of bootstrapping via Clang (DARWIN_USE_GCC=0)
- It's possible but doesn't work yet!
- Needs some work to get sysroot, SDK paths right. See what e.g. macports does for hints.
- bug #758167 is the meta bug for this work.
- Help very much welcome!
  - To attempt a full bootstrap using Clang (this won't work yet, but it'll do something): DARWIN_USE_GCC=0 ./bootstrap-prefix.sh
  - Suggestion: start with trying to build Clang, LLVM, and friends within a fully-built working GCC-bootstrapped Prefix and go from there
  - Suggestion: look at macports patches

M1 macs, etc.

Cannot currently be bootstrapped:

Waiting for GCC support to be merged upstream and in a release (GCC 12?)
- See https://github.com/iains/gcc-darwin-arm64
- We currently use a snapshot in our scripts but it doesn't get to the end, see below.
With a snapshot of the GCC fork/branch, we can get a bit further, but bootstrapping doesn't complete.
- bug #778014 - Prefix: Big Sur ARM (M1 MacBook Pro MYD82LL/A) build failure due to missing symbols
- bug #792780 - sys-devel/binutils-apple fails to build during prefix bootstrap on M1 (Big Sur 11.4)

Works okay!

Still somewhat supported as the supported OS versions age.

Support was dropped recently due to lack of interest, but could be restored with a sponsor/cheerleader.