The parent process doesn't have access to the selected compiler, which
will be important in the next commit.
Fortunately the child process already has a filtered and massaged
ARGV, so it has enough information to build the tab itself.
This adds support for non-Apple GCC compilers in the fails_with code.
A fails_with block for a non-Apple compiler looks like:
fails_with :gcc => '4.8.1' do
cause 'Foo'
end
Non-Apple compilers don't have build numbers, so compiler failures are
based on version strings instead.
Internally non-Apple compilers can be distinguished because they are
passed around as strings instead of symbols.
In addition, this alters the priority list for compilers, with the
following changes:
* Apple GCC 4.2 and LLVM-GCC swap positions, with GCC now taking
priority. (Maybe LLVM-GCC should just go away.)
* Non-Apple GCC compilers are ranked below GCC 4.2 but above LLVM-GCC
and Apple GCC 4.0.
This unifies the logic for selecting a compiler between superenv and
stdenv. A variation of superenv's `determine_cc`, which now returns a
symbol, has been moved into the shared ENV extension. Stdenv uses the
result of this directly (as it's always used symbols), while superenv
translates that back into a compiler string.
This also has the effect of disabling HOMEBREW_USE_(gcc|llvm|clang) in
stdenv, which have already been marked as deprecated for some time, and
enables the HOMEBREW_CC= environment variable syntax from superenv in
stdenv.
This allows overriding the "oldest CPU" behaviour - for instance, to
build Intel bottles for a newer CPU than Core 2, to build a PPC bottle
with or without Altivec on the same computer, etc.
This sets cpp to use the compiler as cpp, and works with scripts which
pass values to cpp on stdin as well as with file arguments.
ClosesHomebrew/homebrew#22155.
An issue could arise when brewing a formula that
has Python 2.x and 3.x support and 2.x is the system Python
but 3.x is a brewed one. The idea about prepending was that
user configured PYTHONPATH could be used in formulae.
Now, instead and if needed, inside the `python do` block
one can still append to PYTHONPATH.
If `depends_on :python => ['modulename', :optional]` then the generated
option is now `--with-python-modulename`, so that it is possible to
actually make depending on python modules optional.
Further, `brew options` becomes more meaningful.
When a formula `depends_on :python` *and* `depends_on :python3`
the `modify_build_environment` method sets the PYTHONPATH
and the Python 3.x requirement then fails because it finds
the sitecustomize.py from Python 2.x in the PYTHONPATH.
