[Mesa-dev] [PATCH] build: Fix AX_PROG_{CC, CXX}_FOR_BUILD macros

[Matt Turner]

On Wed, Nov 21, 2012 at 2:34 AM, Thierry Reding
<thierry.reding at avionic-design.de> wrote:
> On Tue, Nov 20, 2012 at 08:29:04PM +0100, Thierry Reding wrote:
>> On Tue, Nov 20, 2012 at 11:07:03AM -0800, Matt Turner wrote:
>> > On Tue, Nov 20, 2012 at 7:50 AM, Thierry Reding
>> > <thierry.reding at avionic-design.de> wrote:
>> > > Override the cross_compiling and ac_tool_prefix variables by reassigning
>> > > to them instead of redefining the macros. Redefining them will actually
>> > > cause the variable names to be replaced instead of their content.
>> > >
>> > > Furthermore push the definition of CPPFLAGS before running the checks
>> > > for the build tools to avoid the host CPPFLAGS from leaking into the
>> > > build CPPFLAGS.
>> > >
>> > > While at it drop the redefinition of AC_TRY_COMPILER which hasn't been
>> > > used since autoconf 2.50 and make sure that all definitions are properly
>> > > popped when done (LDFLAGS, ac_cv_prog_CPP, ac_cv_prog_CXXCPP).
>> > >
>> > > Signed-off-by: Thierry Reding <thierry.reding at avionic-design.de>
>> > > ---
>> > >  m4/ax_prog_cc_for_build.m4  | 37 +++++++++++--------------------------
>> > >  m4/ax_prog_cxx_for_build.m4 | 38 ++++++++++++--------------------------
>> > >  2 files changed, 23 insertions(+), 52 deletions(-)
>> [...]
>> > Are these changes from upstream? I really have concerns about making
>> > non-trivial changes to these files.
>>
>> No, they're not. I do plan to send these changes upstream, but quite
>> honestly I'm not sure that they'll be accepted given that I have none of
>> the copyright assigment forms filled with the FSF. Looking at the
>> autoconf-archive website doesn't actually say anything about copyright
>> assignment, but as the project is hosted on GNU I'm a bit sceptical.
>> Also note that AX_PROG_CXX_FOR_BUILD doesn't actually exist upstream. I
>> essentially copied it from AX_PROG_CC_FOR_BUILD.
>>
>> I'm actually a bit confused as to why the original cross-compilation
>> patches that I sent in worked at all (and I'm sure they did because I
>> tested them fairly extensively at the time), but looking at configure
>> as generated with the macros as they are in the repository right now,
>> things are severely broken. Running the configure script shows a bunch
>> of
>>
>>       checking for 2... no
>>
>> messages, and cross-compiling doesn't actually succeed. With the above
>> patches I've verified that Mesa cross-builds from x86_64 to ARM.
>>
>> Still, if you have any doubts I can try feeding those changes upstream
>> and see what comes of it. If that happens we can easily sync the changes
>> back by copying the files.
>
> For reference, I've submitted patches for both macros upstream. They are
> available here:
>
>         http://savannah.gnu.org/patch/index.php?7890
>         http://savannah.gnu.org/patch/index.php?7891
>
> Thierry

Okay, looks like you've done your part. I just pushed this patch. Thanks!