[cmake-developers] [CMake 0012258]: include_directories(SYSTEM ...) not functional with GNU Makefiles

[Mantis Bug Tracker]

The following issue has been SUBMITTED. 
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http://public.kitware.com/Bug/view.php?id=12258 
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Reported By:                Campbell Barton
Assigned To:                
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Project:                    CMake
Issue ID:                   12258
Category:                   CMake
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
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Date Submitted:             2011-06-09 00:42 EDT
Last Modified:              2011-06-09 00:42 EDT
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Summary:                    include_directories(SYSTEM  ...) not functional with
GNU Makefiles
Description: 
There were some system headers giving warnings compiling on linux,
since I like to have warnings as errors, and not edit system headers,
I used:
 include_directories(SYSTEM dir1 dir2 ...)
... for system directories only.

However this does not result in -isystem being used in C because
GNU.cmake does not set:
 set(CMAKE_INCLUDE_SYSTEM_FLAG_C "-isystem ")
... as it does for C++.

I tried adding this directly after the project(), call (beforehand it
fails to have any effect):

       if(CMAKE_COMPILER_IS_GNUCC)
               if(NOT APPLE)
                       set(CMAKE_INCLUDE_SYSTEM_FLAG_C "-isystem ")
               endif()
       endif()


So now it almost works, but I've noticed that If
"include_directories(SYSTEM" is called after a non system include, ALL
includes then use -isystem.

Putting "include_directories(SYSTEM" first mostly works out OK, but I
found a few cases where the order isn't so easy to set in our own
CMakeLists.txt and still incorrectly uses -isystem where it shouldn't.
Also found using the BEFORE / AFTER arguments to include_directories(
doesn't make any difference to the use of -isystem.

Is this a known problem or is there a way to get this working?
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Issue History 
Date Modified    Username       Field                    Change               
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2011-06-09 00:42 Campbell BartonNew Issue                                    
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