Implement fails_with for non-Apple compilers

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.

1 files changed, 6 insertions, 1 deletions

diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index bbcb1dab2..29e87af06 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -212,7 +212,12 @@ class Formula
   def fails_with? cc
     cc = Compiler.new(cc) unless cc.is_a? Compiler
     (self.class.cc_failures || []).any? do |failure|
-      failure.compiler == cc.name && failure.build >= cc.build
+      if cc.version
+        # non-Apple GCCs don't have builds, just version numbers
+        failure.compiler == cc.name && failure.version >= cc.version
+      else
+        failure.compiler == cc.name && failure.build >= cc.build
+      end
     end
   end