ENV.cc= and ENV.cxx= are private
Add accessor for HOMEBREW_CC
dyld-headers 239.4

Update to latest release from Apple, update patch.

Closes #29161.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
cctools-headers 845

Update to latest cctools and XNU from Apple, use HTTPS download links.

Closes #29156.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
Remove hardcoded reference to ENV