Where should I put sysroot for cross compiling toolchain?

[AlynxZhou]

Output of brew config

HOMEBREW_VERSION: 4.5.7-19-g09eaf14
ORIGIN: https://github.com/Homebrew/brew
HEAD: 09eaf1495a86e30089a4369f498dce357dde385e
Last commit: 11 hours ago
Branch: master
Core tap HEAD: d5f48de1bdbcdd016919f9138181b2cd7b4b2be8
Core tap last commit: 8 hours ago
Core tap JSON: 16 Jun 08:31 UTC
Core cask tap JSON: 16 Jun 08:51 UTC
HOMEBREW_PREFIX: /opt/homebrew
HOMEBREW_CASK_OPTS: []
HOMEBREW_EDITOR: emacsclient --create-frame --alternate-editor=""
HOMEBREW_MAKE_JOBS: 8
HOMEBREW_SORBET_RUNTIME: set
Homebrew Ruby: 3.4.4 => /opt/homebrew/Library/Homebrew/vendor/portable-ruby/3.4.4/bin/ruby
CPU: octa-core 64-bit arm_firestorm_icestorm
Clang: 17.0.0 build 1700
Git: 2.49.0 => /opt/homebrew/bin/git
Curl: 8.7.1 => /usr/bin/curl
macOS: 15.5-arm64
CLT: 16.4.0.0.1.1747106510
Xcode: N/A
Rosetta 2: false

Output of brew doctor

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Warning: Some installed kegs have no formulae!
This means they were either deleted or installed manually.
You should find replacements for the following formulae:
  arm-none-eabi-newlib

Warning: Some installed formulae are deprecated or disabled.
You should find replacements for the following formulae:
  neofetch

Warning: Putting non-prefixed coreutils in your path can cause GMP builds to fail.

Warning: You have uncommitted modifications to Homebrew/homebrew-core.
If this is a surprise to you, then you should stash these modifications.
Stashing returns Homebrew to a pristine state but can be undone
should you later need to do so for some reason.
  cd /opt/homebrew/Library/Taps/homebrew/homebrew-core && git stash -u && git clean -d -f

Uncommitted files:
  ?? Formula/a/arm-none-eabi-newlib.rb

Description of issue

We already have formula for arm-none-eabi-gcc, however, there is no C library for it, so it's not able to cross compile binaries for that arch. And I am trying to package arm-none-eabi-newlib which is a C library for embedded systems.

Now I can correctly build and install arm-none-eabi-newlib. But the problem is arm-none-eabi-gcc cannot see it. Typically in Linux, we use sysroot for cross compiling toolchains, for example /usr/arm-none-eabi, and put all headers, objects and libraries into that directory, so arm-none-eabi-gcc can find arm-none-eabi-newlib files here.

However, Homebrew puts packages file into different Cellar dirs, so they cannot see each other. Where should I choose to make a sysroot, so cross compiling toolchain can put files into that dir and share them?

[AlynxZhou]

I think we need a standard to put cross compiling toolchain sysroot, because obviously we cannot install target libs into $HOMEBREW_PREFIX/lib, could we create directories like $HOMEBREW_PREFIX/arm-none-eabi?