This code originated in a slightly different form in 8e88b22fd1ec65a344ce6e4facd6dad4b415b2ad:
8e88b22fd1/Library/Homebrew/extend/ENV.rb (L30-L32)
Back then, MacOS.default_compiler could return nil, which meant
ENV.compiler could do the same. This code was carried forward as the
surrounding code changed. At this point it should be unreachable.
Formula::DATA only worked by accident of implementation; DATA during the
build is actually Object::DATA, so we should mirror that here.
This reverts commit b12444ba6e1ac1d596a70ff4c777d9386d0791ac.
Instances of `IOPatch` created by `patch :DATA` are not affected by re-setting
the `DATA` constant of the `Formula` instance. For these patches, we iterate
through the `patchlist` and use `instance_variable_set` to attach data.
A bit hacky, but `patchlist` has no write accessors so there isn't a clean way
to modify patch contents.
On older Apple compilers "-O4" is known to cause build errors. On recent
clang, it's the same as "-O3" and you have to pass "-O3 -flto" to get
the old behavior.
This requires hitting the network, which makes the first invocation
slow. The results are inaccurate as it only pulls down the first page of
results. It is also prone to false-positives.
A better implementation is welcome, but in the years since I wrote this
code I can't think of a single time where I found it useful.
It is activated by the same mechanism as the Homebrew/versions compilers
which now check if the GCC formula uses the same, correct version.
References Homebrew/homebrew#28418.
`MacOS::Xcode.without_clt? && MacOS.sdk_path.nil?` should never be true.
In its earliest form, this would raise a bare RuntimeError in an effort
to have the bug reported. Later, it was changed to silently disable
superenv. But we don't want to do that. If there's a bug, or the user's
system is misconfigured, we want to know, so that we can fix the bug, or
the user can fix their system. So let's remove the condition.
