Re: [gpsd-dev] [gpsd-commit-watch] [SCM] GPSD branch, master, updated. release-3.9-547-gcbf524c

[Eric S. Raymond]

Greg Troxel <address@hidden>:
> Stepping back from autoconf/scons/etc., I mean 'configure time' to be
> the things that happen to figure out the system, as opposed to running
> the (maybe cross) compiler to build objects for the target.
> 
> First, for header files we need (that are not required by
> posix, or for which we cut slack to nonconforming implemenations), the
> build needs to determine if they are present.  Present of course means
> "usable by the compiler, which may be cross".

Right.  The problem with any check for file location or endianness run
*by scons* is that it will check the state of the build host, not the
target.

> So given that endian.h is in different places (actually, and posix seems
> not to specify this), I think the following steps should be happening:
> 
>   check for presence of endian.h
>   (if not found) check for presence of sys/endian.h
> 
> when building the endian test program

If you do it this way, you lose when the location of endian.h on the target 
system is different from where it is on the host.  This is why it's
better to extract information from the target compiler's #ifdefs than 
to run tests in scons.
-- 
                <a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>

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