Filter list before mapping it

Library/ENV/4.3/cc

@@ -214,7 +214,7 @@ class Cmd
     # We reject brew's lib as we explicitly add this as a -L flag, thus it
     # is given higher priority by cc, so it surpasses the system libpath.
     # NOTE this only counts if Homebrew is installed at /usr/local
-    syspath.map{|d| "#{d}/lib" }.reject{|d| d == "#{brewfix}/lib" }
+    syspath.reject { |d| d == brewfix }.map! { |d| File.join(d, "lib") }
   end
   def cpath
     cpath  = path_split("CMAKE_PREFIX_PATH").map! { |d| File.join(d, "include") }