graphics/opencv2-core: compiler error on CURRENT: error: 'stddef.h' file not found

[Mark Millard]

O. Hartmann ohartman at zedat.fu-berlin.de wrote on Fri Oct 7 08:26:27 UTC 2016 . . .

. . . of having problems with not finding <stddef.h> during some port builds.


Is there a difference in the -isystem command line options for c++ for the working vs. failing contexts?

I will presume that there is based on the following. . . (At least it gives you something to look into.)



The issue is not specific to just graphics/opencv-core and graphics/blender ports: others also have problems with the use of -isystem for C++ compiles. See:

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=213217

in particular Comment #2 from Dimitry Andric.

The problem is in how -isystem is used vs. what is needed for libc++ 3.8.0 .

From O. Hartmann's message text:

. . .
> -isystem /usr/local/include/eigen3 -isystem /usr/include/include -O2 -pipe -O3
. . .
> In file included from /usr/include/c++/v1/algorithm:624: In file included
> from /usr/include/c++/v1/initializer_list:47: /usr/include/c++/v1/cstddef:43:15: fatal
> error: 'stddef.h' file not found #include_next <stddef.h> ^ ---
. . .
> In file included from /usr/include/c++/v1/algorithm:624: In file included
> from /usr/include/c++/v1/initializer_list:47: /usr/include/c++/v1/cstddef:43:15: fatal
> error: 'stddef.h' file not found #include_next <stddef.h>


Dimitry wrote for this issue of <stddef.h> not being found:

> Summary: If for some reason you must completely rebuild the header search path
> from scratch, you need to add  -isystem /usr/include/c++/v1 *before* -isystem
> /usr/include.  But it is better not to do this at all. :)

There is more background/supporting information in that comment.

===
Mark Millard
markmi at dsl-only.net