Post-install audit for shadowed header files

Library/Homebrew/cmd/audit.rb

@@ -567,6 +567,7 @@ class FormulaAuditor
     audit_check_output(check_generic_executables(f.bin))
     audit_check_output(check_non_executables(f.sbin))
     audit_check_output(check_generic_executables(f.sbin))
+    audit_check_output(check_shadowed_headers)
   end
 
   def audit

Library/Homebrew/formula_cellar_checks.rb

@@ -106,4 +106,23 @@ module FormulaCellarChecks
       EOS
     ]
   end
+
+  def check_shadowed_headers
+    return if f.keg_only? || !f.include.directory?
+
+    files  = relative_glob(f.include, "**/*.h")
+    files &= relative_glob("#{MacOS.sdk_path}/usr/include", "**/*.h")
+    files.map! { |p| File.join(f.include, p) }
+
+    return if files.empty?
+
+    ["Header files that shadow system header files were installed to \"#{f.include}\".",
+     "The offending files are:  \n  #{files * "\n  "}"]
+  end
+
+  private
+
+  def relative_glob(dir, pattern)
+    Dir.chdir(dir) { Dir[pattern] }
+  end
 end

Library/Homebrew/formula_installer.rb

@@ -384,6 +384,7 @@ class FormulaInstaller
       audit_lib
       audit_man
       audit_info
+      audit_include
     end
 
     c = Caveats.new(f)
@@ -671,6 +672,10 @@ class FormulaInstaller
     print_check_output(check_infopages)
   end
 
+  def audit_include
+    print_check_output(check_shadowed_headers)
+  end
+
   private
 
   def hold_locks?