Re: having trouble with XTRA_CFLAGS showing up on AM_CXXFLAGS

[John W. Eaton]

On 02/06/2016 10:42 PM, Carnë Draug wrote:
> Hi
>
> I've been playing around with our configure and I'm having a problem
> that maybe someone can help me with.
>
> I'm adding a flag to XTRA_CFLAGS in our configure script and it seems to
> somehow be creeping into AM_CXXFLAGS.  The weird thing is that looking into
> the generate Makefiled, it is not there.  However, when I run "make -n", I
> see it showing up in AM_CXXFLAGS.
>
> Here's what I've been doing.  I've been adding the following lines to
> configure.ac:
>
>      XTRA_CFLAGS="$XTRA_CFLAGS -std=c11"
>      XTRA_CXXFLAGS="$XTRA_CXXFLAGS -std=c++11"
>      CFLAGS="$CFLAGS -std=c11"
>      CXXFLAGS="$CXXFLAGS -std=c++11"
>
> After running configure, everything looks fine, the displayed resume
> looks correct.  However, once the build actually starts I get warnings
> like:
>
>        GEN      libinterp/octave-value/ov-flt-re-mat.df
>      cc1plus: warning: command line option ‘-std=c11’ is valid for
> C/ObjC but not for C++
>
> And indeed, running "make -n", I get g++ being called with -std=c11.  For
> example, the recipe for octave-value/ov-flt-re-mat.df
>
>      g++ -E -DHAVE_CONFIG_H -I. -I/home/carandraug/dev/octave  \
>        -I. [....] \
>        -std=c11 -pthread -fopenmp [...] \
>        [...]
>      mv libinterp/octave-value/ov-flt-re-mat.df-t
> libinterp/octave-value/ov-flt-re-mat.df
>
> Anyone can explain me what I'm doing wrong?

Oops, I fixed it in this changeset:

  http://hg.savannah.gnu.org/hgweb/octave/rev/b7a191eb0c3c

Thanks.

jwe