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Subject: Re: [Qemu-devel] [PATCH] configure: Detect when glibc implements
 makecontext() to always fail
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: qemu-devel@nongnu.org, patches@linaro.org

Am 13.10.2011 16:26, schrieb Andreas F=E4rber:
> Am 12.10.2011 18:21, schrieb Peter Maydell:
>> Improve the configure test for presence of ucontext functions by
>> making linker warnings fatal; this allows us to detect when we are
>> linked with a glibc which implements makecontext() to always return
>> ENOSYS.
>>
>> Signed-off-by: Peter Maydell<peter.maydell@linaro.org>
>=20
> Tested-by: Andreas F=E4rber <afaerber@suse.de>
>=20
>> ---
>> Compiling on an Ubuntu Natty ARM host will hit this.
>=20
> Works on Ubuntu Maverick ARM host as well.

Erm... This works great, also for accept4(), on Linux, but it's not
portable. Apple ld(1) doesn't seem to have --fatal-warnings.

http://developer.apple.com/library/mac/#documentation/Darwin/Reference/Ma=
nPages/Xcode-3.2.5/man1/ld.1.html

Sun/Oracle ld(1) does seem to have it as alias to -z fatal-warnings.

http://download.oracle.com/docs/cd/E19963-01/html/821-1461/ld-1.html

So, we'd have to check for valid linker options first?

Andreas