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.
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.
Symlinks in opt and LinkedKegs point directly at a keg in the cellar, so
only resolving one symlink should suffice, and make it clear what path
we are actually interested in.
Rationale: our arg refurbishment is normally only turned on when
called via the `make` wrapper, for compatibility reasons. However,
there are numberous places we'd like this to be turned on elsewhere,
like software that builds via `python setup.py` where bad flags from
the system python can be pulled in.
This helper appends 'O' to CCCFG, which enables refurbishment for
all calls of the compiler shims.
This method is for internal use only. It is unsuitable for use in
formulae, which should use install_symlink to create relative symlinks.
Thus callers are required to pass a Pathname, not a string, and we can
remove this conditional.
Further, if src is not absolute, then src.relative_path_from(dirname)
will fail. All callers currently pass absolute pathnames. Therefore we
don't need to call expand_path when printing it.
Turns out that this doesn't really work at all. `brew install` _never_
reuses options in the first place, and using this option with `brew
upgrade` results in some nasty corner cases in passing options to
dependencies.
Previously, with nested arrays, the Symbol#to_proc would iterate over
the first item in the nested array instead of the array itself, e.g.:
[[1,2], [3,4]].map(&:first) #=>
NoMethodError: undefined method `first' for 1:Fixnum
