Move dump_build_env to utils and use during installs too.

Library/Homebrew/install.rb

@@ -66,9 +66,7 @@ def install f
 
   if ARGV.verbose?
     ohai "Build Environment"
-    %w[PATH CFLAGS LDFLAGS CPPFLAGS MAKEFLAGS CC CXX MACOSX_DEPLOYMENT_TARGET PKG_CONFIG_PATH].each do |env|
+    dump_build_env ENV
-      puts "#{env}: #{ENV[env]}" unless ENV[env].to_s.empty?
-    end
   end
 
   build_time = nil

Library/Homebrew/utils.rb

@@ -213,3 +213,12 @@ def nostdout
     end
   end
 end
+
+def dump_build_env env
+  puts "\"--use-llvm\" was specified" if ARGV.include? '--use-llvm'
+
+  %w[CC CXX LD CFLAGS CXXFLAGS CPPFLAGS LDFLAGS MACOSX_DEPLOYMENT_TARGET MAKEFLAGS PATH PKG_CONFIG_PATH HOMEBREW_USE_LLVM].each do |k|
+    value = env[k]
+    puts "#{k}: #{value}" if value
+  end
+end

bin/brew

@@ -69,15 +69,6 @@ PATH: #{ENV['PATH']}
 EOS
 end
 
-def dump_build_env env
-  puts "\"--use-llvm\" was specified" if ARGV.include? '--use-llvm'
-
-  %w[CC CXX LD CFLAGS CXXFLAGS CPPFLAGS LDFLAGS MAKEFLAGS PATH PKG_CONFIG_PATH HOMEBREW_USE_LLVM].each do |k|
-    value = env[k]
-    puts "#{k}: #{value}" if value
-  end
-end
-
 begin
   require 'brew.h'