1 files changed, 31 insertions, 0 deletions
diff --git a/Library/Homebrew/build_environment.rb b/Library/Homebrew/build_environment.rb
index 701cd414e..05ac9a43e 100644
--- a/Library/Homebrew/build_environment.rb
+++ b/Library/Homebrew/build_environment.rb
@@ -30,3 +30,34 @@ module BuildEnvironmentDSL
     @env.merge(settings)
   end
 end
+
+module Homebrew
+  def build_env_keys(env)
+    %w[
+      CC CXX LD OBJC OBJCXX
+      HOMEBREW_CC HOMEBREW_CXX
+      CFLAGS CXXFLAGS CPPFLAGS LDFLAGS SDKROOT MAKEFLAGS
+      CMAKE_PREFIX_PATH CMAKE_INCLUDE_PATH CMAKE_LIBRARY_PATH CMAKE_FRAMEWORK_PATH
+      MACOSX_DEPLOYMENT_TARGET PKG_CONFIG_PATH PKG_CONFIG_LIBDIR
+      HOMEBREW_DEBUG HOMEBREW_MAKE_JOBS HOMEBREW_VERBOSE
+      HOMEBREW_SVN HOMEBREW_GIT
+      HOMEBREW_SDKROOT HOMEBREW_BUILD_FROM_SOURCE
+      MAKE GIT CPP
+      ACLOCAL_PATH PATH CPATH].select { |key| env.key?(key) }
+  end
+
+  def dump_build_env(env, f = $stdout)
+    keys = build_env_keys(env)
+    keys -= %w[CC CXX OBJC OBJCXX] if env["CC"] == env["HOMEBREW_CC"]
+
+    keys.each do |key|
+      value = env[key]
+      s = "#{key}: #{value}"
+      case key
+      when "CC", "CXX", "LD"
+        s << " => #{Pathname.new(value).realpath}" if File.symlink?(value)
+      end
+      f.puts s
+    end
+  end
+end