Set CC and CXX with superenv (again)

It was dumb to have make call different compilers to configure depending on the `servile?` flag. This is not a route to reliability.

Instead now we set CC (formula that break if CC is set like Jack be damned, their build-systems are just plain broken and should not be supported). When cc is called we examine HOMEBREW_CC, otherwise we instantiate the tool that was called, just like the formula's build-system will expect.

Fixes Homebrew/homebrew#14659 (though the build fails later for me, with the same error for stdenv and superenv).

Library/ENV/4.3/cc

@@ -1,13 +1,9 @@
 #!/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby -W0
+
 #TODO make it work with homebrew/dupes/gcc
 #TODO? If we find -mmacosx-version-min=10.8, change sdkroot? warn visibly if no such SDK?
 #TODO fix pkg-config files, should point to /usr/local or /usr/local/opt
-#TODO for easier to understand code, don't monkey-patch ENV, just set via a hash from a helper class
 #TODO create mechanism to specify build effects like %w{-O0 -O4 vanilla-arg-parsing sdk=10.6} etc.
-#TODO DSL for lame-env (and rename to typical-env or something better)
-#TODO consider always setting CC to cc and instead having HOMEBREW_CC to force cc choice in end toolchain
-#     in verbose mode print out things like "gcc called, but redirecting to clang" if that happens
-#TODO `brew sh`: https://github.com/mxcl/homebrew/issues/14381#issuecomment-8017538
 
 require "#{File.dirname __FILE__}/../libsuperenv"
 require 'set'
@@ -15,13 +11,6 @@ require 'set'
 def cccfg? flags
   flags.split('').all?{|c| ENV['HOMEBREW_CCCFG'].include? c } if ENV['HOMEBREW_CCCFG']
 end
-def servile?
-  # we are servile when we are called from configure etc.
-  # * we give the callee the tools it asks for
-  # * we leave ARGV alone
-  # when callee is make we optimize and force HOMEBREW_CC
-  not cccfg? 'O'
-end
 def nclt?
   $sdkroot != nil
 end
@@ -51,20 +40,21 @@ class Cmd
     end
   end
   def tool
-    @tool ||= if servile? or @arg0 == 'ld'
-      @arg0
-    elsif @arg0.include? '++'
-      if ENV['HOMEBREW_CC'].chuzzle =~ /gcc/
+    @tool ||= case @arg0
+    when 'ld' then 'ld'
+    when 'cc' then ENV['HOMEBREW_CC']
+    when 'c++'
+      if ENV['HOMEBREW_CC'] =~ /gcc/
         'g++'
       else
         'clang++'
       end
     else
-      ENV['HOMEBREW_CC'].chuzzle or 'clang'
+      @arg0
     end
   end
   def args
-    args = if servile? or tool == 'ld'
+    args = if not cccfg? 'O' or tool == 'ld'
       @args.dup
     else
       refurbished_args
@@ -158,6 +148,11 @@ end
 ####################################################################### sanity
 abort "The build-tool has reset ENV. --env=std required." unless ENV['HOMEBREW_BREW_FILE']
 
+case ENV['HOMEBREW_CC'].chuzzle when 'cc', nil
+  # those values are not allowed
+  ENV['HOMEBREW_CC'] = 'clang'
+end
+
 ######################################################################### main
 cmd = Cmd.new($0, ARGV)
 exec "xcrun", cmd.tool, *cmd.args

Library/ENV/4.3/make

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 export HOMEBREW_CCCFG="O$HOMEBREW_CCCFG"
 if [ $(basename "$0") == "bsdmake" ]; then
   pwd="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

Library/Homebrew/superenv.rb

@@ -41,7 +41,8 @@ class << ENV
   def setup_build_environment
     reset
     check
-    ENV['LD'] = 'cc'
+    ENV['CC'] = ENV['LD'] = 'cc'
+    ENV['CXX'] = 'c++'
     ENV['MAKEFLAGS'] ||= "-j#{determine_make_jobs}"
     ENV['PATH'] = determine_path
     ENV['PKG_CONFIG_PATH'] = determine_pkg_config_path
@@ -198,13 +199,16 @@ class << ENV
   end
   alias_method :j1, :deparallelize
   def gcc
-    ENV['HOMEBREW_CC'] = "gcc"
+    ENV['CC'] = ENV['HOMEBREW_CC'] = "gcc"
+    ENV['CXX'] = "g++"
   end
   def llvm
-    ENV['HOMEBREW_CC'] = "llvm-gcc"
+    ENV['CC'] = ENV['HOMEBREW_CC'] = "llvm-gcc"
+    ENV['CXX'] = "g++"
   end
   def clang
-    ENV['HOMEBREW_CC'] = "clang"
+    ENV['CC'] = ENV['HOMEBREW_CC'] = "clang"
+    ENV['CXX'] = "clang++"
   end
   def make_jobs
     ENV['MAKEFLAGS'] =~ /-\w*j(\d)+/