[Python-Dev] Any reason why CPPFLAGS not used in compiling?

["Martin v. Löwis"]

Brett C. wrote:
>> How did you notice that? For LDFLAGS, Makefile.pre.in has
>>
>> LDFLAGS=        @LDFLAGS@
>>
>> This does *not* mean that the value from the environment is used.
>> Instead, it means that configure computes the value of LDFLAGS
>> when it generates Makefile.in. For CPPFLAGS, configure has nothing
>> to compute, so Makefile.pre.in just has the static value for
>> CPPFLAGS.
>>
> 
> I am not so sure that is true.  Checking configure.in, there is no 
> mention of CPPFLAGS anywhere.

Right. That's what I meant when I said "has nothing to compute", so
it does not even mention CPPFLAGS.

> And yet if I modify the definition of 
> CPPFLAGS in Makefile.pre.in to ``-I. -I./Include @CPPFLAGS@`` it ends up 
> containing the value I have for the environment variable at the end of 
> it.  I think the '@@' syntax uses a value from configure.in if it is 
> defined else it defaults to the value the shell has.

Indeed, that seems to be the case. However, absence of @CPPFLAGS@
means that Makefile.pre will just use the static value from
Makefile.pre.in.

Whether or not adding @CPPFLAGS@ to the end is the right thing,
I don't know.

Regards,
Martin