[lmi] wx configure and CXXFLAGS [Was: Building lmi with pre-wx-2.9.5 snapshot]

[Greg Chicares]

On 2013-07-11 22:51, Vadim Zeitlin wrote:
> On Thu, 11 Jul 2013 14:06:57 +0000 Greg Chicares <address@hidden> wrote:
[...]
> GC> (2) Unrelated question: when building wx itself, using
> GC>   ../configure [...options...] && make && make install
> GC> can I add my own CXXFLAGS in configure's options-list?
> 
>  I'm afraid there is no way to do it now. Our configure overrides CXXFLAGS
> with its own values, which is wrong, but too difficult to change by now.

Have you considered supporting a variable like EXTRA_CXXFLAGS (or adding
an '--extra_cxxflags=' option)? That wouldn't require changing the way
CXXFLAGS is overridden; it could just be appended as a final step.

CFLAGS, CPPFLAGS, and LDFLAGS could be treated the same way.

> The usual trick I use to work around this is to pass "CXX" (and "CC", if
> relevant) values to make on its command line, e.g. I'd do
> 
>       make CXX="g++ --param ..."
> 
> to achieve what you'd like to. This is not as convenient as using configure
> but in practice works without any problems.

Here's an actual use case where that's inconvenient. Today in lmi HEAD
we have this:

  
http://git.savannah.gnu.org/cgit/lmi.git/tree/install_wx.make?id=289f82c0b2bcfffb50d3a7d347bd218c145a53a0

wx_cxx_flags   := -fno-omit-frame-pointer -std=c++11

config_options = \
...
    CXX='$(mingw_bin_dir)/$(triplet_prefix)g++ $(wx_cxx_flags)' \

Eleven programs in the toolchain are explicitly specified like that
(nm, ranlib, strip, windres, etc.). I'd rather specify none, and let
'configure' deduce them from '--host='. That would make it simpler
to support native as well as cross builds.

Of course, using a hand-written makefile to invoke 'configure' may
be uncommon, but there must be other reasonable use cases that need
to specify extra FLAGS.