From 583e3a68758f02060099994b1fd41b823ddc2bab Mon Sep 17 00:00:00 2001
From: Christof Kaufmann <christof.kaufmann@hs-bochum.de>
Date: Thu, 9 Mar 2017 16:13:46 +0100
Subject: [PATCH] cmake: Avoid adding default path as system directory for GCC
 6.x

This is a completion for PR #7390 and fixes #6517 and #815.
---
 cmake/OpenCVPCHSupport.cmake | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/cmake/OpenCVPCHSupport.cmake b/cmake/OpenCVPCHSupport.cmake
index 29f21d8..4f9be6d 100644
--- a/cmake/OpenCVPCHSupport.cmake
+++ b/cmake/OpenCVPCHSupport.cmake
@@ -65,6 +65,9 @@ MACRO(_PCH_GET_COMPILE_FLAGS _out_compile_flags)
         ocv_is_opencv_directory(__result ${item})
         if(__result)
           LIST(APPEND ${_out_compile_flags} "${_PCH_include_prefix}\"${item}\"")
+        elseif(CMAKE_COMPILER_IS_GNUCXX AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS "6.0" AND
+               item MATCHES "/usr/include$")
+          # workaround for GCC 6.x bug
         else()
           LIST(APPEND ${_out_compile_flags} "${_PCH_isystem_prefix}\"${item}\"")
         endif()
@@ -75,6 +78,9 @@ MACRO(_PCH_GET_COMPILE_FLAGS _out_compile_flags)
         ocv_is_opencv_directory(__result ${item})
         if(__result)
           LIST(APPEND ${_out_compile_flags} "${_PCH_include_prefix}\"${item}\"")
+        elseif(CMAKE_COMPILER_IS_GNUCXX AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS "6.0" AND
+               item MATCHES "/usr/include$")
+          # workaround for GCC 6.x bug
         else()
           LIST(APPEND ${_out_compile_flags} "${_PCH_isystem_prefix}\"${item}\"")
         endif()
-- 
2.7.4