Weaken PIE configure test to a compile test

[Carlos O'Donell]

On Mon, May 28, 2012 at 6:11 PM, Joseph S. Myers
<joseph@codesourcery.com> wrote:
> One remaining configure test that produces different results in
> bootstrap builds because it tries linking against a preexisting libc
> is the test for position-independent executable support.
>
> I propose this patch, weakening it to a compile test.  (Really it
> could probably be eliminated completely and PIE support hardwired to
> be on; this is just a more conservative patch, and only fairly limited
> cleanups are made possible through hardwiring PIE support on.)  If for
> some reason PIE support is problematic for an architecture it's
> certainly better for GCC to diagnose that at compile time rather than
> accept the option and then fail to link.  But given PIC support, there
> isn't much more involved in PIE support, and part of what is involved
> is bits of statically linked libc code being suitable for linking into
> PIEs - something that of course is a property of the newly built libc,
> not the old one.
>
> Tested x86_64.  I am not aware of any systems supported by libc or
> ports that do not support PIEs.  (EGLIBC has hardwired the answer to
> this test to "yes" for the past five years and I see no sign of Debian
> having needed to revert that for any system.)
>
> 2012-05-28  Joseph Myers  <joseph@codesourcery.com>
>
>        * configure.in (libc_cv_fpie): Weaken to a compile test using
>        LIBC_TRY_CC_OPTION.
>        * configure: Regenerated.

I agree with the rationale and this looks good.

Cheers,
Carlos.