separate ENV/pkgconfig dirs by OS version

Closes Homebrew/homebrew#16063.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Library/Homebrew/extend/ENV.rb

@@ -67,8 +67,8 @@ module HomebrewEnvExtension
     paths = []
     paths << HOMEBREW_PREFIX/'lib/pkgconfig'
     paths << HOMEBREW_PREFIX/'share/pkgconfig'
-    paths << HOMEBREW_REPOSITORY/'Library/ENV/pkgconfig' if MacOS.version >= :mountain_lion
-    paths << HOMEBREW_REPOSITORY/'Library/ENV/pkgconfigLeopard' if MacOS.version <= :leopard
+    paths << HOMEBREW_REPOSITORY/'Library/ENV/pkgconfig/mountain_lion' if MacOS.version >= :mountain_lion
+    paths << HOMEBREW_REPOSITORY/'Library/ENV/pkgconfig/leopard' if MacOS.version <= :leopard
     paths << '/usr/lib/pkgconfig'
     paths.select { |d| File.directory? d }.join(':')
   end

Library/Homebrew/superenv.rb

@@ -121,7 +121,7 @@ class << ENV
     # we put our paths before X because we dupe some of the X libraries
     paths << "#{MacSystem.x11_prefix}/lib/pkgconfig" << "#{MacSystem.x11_prefix}/share/pkgconfig" if x11?
     # Mountain Lion no longer ships some .pcs; ensure we pick up our versions
-    paths << "#{HOMEBREW_REPOSITORY}/Library/ENV/pkgconfig" if MacOS.version >= :mountain_lion
+    paths << "#{HOMEBREW_REPOSITORY}/Library/ENV/pkgconfig/mountain_lion" if MacOS.version >= :mountain_lion
     paths.to_path_s
   end