Support lld + update toolchains

[def-]

Incremental compile time improves from 6min28s to 13s on my system by using lld.

I'm failing to build locally but that might be a me problem, I had similar errors before:

[INFO ]  Installing core C gcc compiler
[EXTRA]    Configuring core C gcc compiler
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:496:3: error: '__abi_tag__' attribute only applies to structs, variables, functions, and namespaces
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:496:57: error: expected ';' at end of declaration list
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:498:68: error: too many arguments provided to function-like macro invocation
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:504:68: error: too many arguments provided to function-like macro invocation
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:575:3: error: '__abi_tag__' attribute only applies to structs, variables, functions, and namespaces
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:575:57: error: expected ';' at end of declaration list
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:577:68: error: too many arguments provided to function-like macro invocation
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:583:68: error: too many arguments provided to function-like macro invocation
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:683:55: error: too many arguments provided to function-like macro invocation
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:683:35: error: declaration conflicts with target of using declaration already in scope
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:684:3: error: expected expression
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:685:2: error: expected ';' at end of declaration
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:688:55: error: too many arguments provided to function-like macro invocation
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:688:35: error: declaration conflicts with target of using declaration already in scope
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:689:3: error: expected expression
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:690:2: error: expected ';' at end of declaration
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:693:55: error: too many arguments provided to function-like macro invocation
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:693:35: error: declaration conflicts with target of using declaration already in scope
[ERROR]    /Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include/c++/v1/__locale:694:3: error: expected expression
[ERROR]    fatal error: too many errors emitted, stopping now [-ferror-limit=]
[ERROR]    make[1]: *** [/private/tmp/aarch64-unknown-linux-gnu-20241210-83193-8ybdbn/mnt/build/.build/aarch64-unknown-elf/src/gcc/gcc/config/aarch64/x-aarch64:3: driver-aarch64.o] Error 1

I'm also not sure how to upload the artifacts for this to homebrew. @benesch I guess you have access to do so.