From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?ISO-8859-1?Q?J=F6rg?= Krause <joerg.krause@embedded.rocks>
Date: Sat, 14 Jan 2017 16:34:05 +0100
Subject: [Buildroot] [autobuild.buildroot.net] Your build results for
	2017-01-13
In-Reply-To: <20170114072939.0FF8220B7E@mail.free-electrons.com>
References: <20170114072939.0FF8220B7E@mail.free-electrons.com>
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To: buildroot@busybox.net

Hi,

On Sat, 2017-01-14 at 08:29 +0100, Thomas Petazzoni wrote:
> Hello,
> 
> This is the list of Buildroot build failures that occured on
> 2017-01-13, and for which you are a registered architecture developer
> or package developer. Please help us improving the quality of
> Buildroot by investigating those build failures and sending patches
> to
> fix them. Thanks!
> 
> Build failures related to your packages:
> 
> ?????????arm |???????????????????????mpd-0.20 | http://autobuild.buil
> droot.net/results/da259e57f96cf0dd6fbac9fe44826e93f986d9e9
> ???????sparc |???????????????????????mpd-0.20 | http://autobuild.buil
> droot.net/results/242b4cff0257f353ce6b2df744c51488dbc0d2c5
> ???????sparc |???????????????????????mpd-0.20 | http://autobuild.buil
> droot.net/results/8d50a025ffcc5b3408fa27f59f0cd896616dc2c6
> ????????i686 |???????????????????????mpd-0.20 | http://autobuild.buil
> droot.net/results/362233e40960f8f0410bf24404fa05ce38cbfb56
> ???????nios2 |???????????????????????mpd-0.20 | http://autobuild.buil
> droot.net/results/a5506440bd02726d6e3b0240ece876c73b92b546
> ???????sparc |???????????????????????mpd-0.20 | http://autobuild.buil
> droot.net/results/e964b1f0ac39ec9c14f5e3b368132d8dc671c249
> 

The error message is:

error: 'exception_ptr' in namespace 'std' does not name a type

The problem is related to this bug report [1]. Both std::future and
std::exception_prt are only enabled in libstdc++ if
'ATOMIC_INT_LOCK_FREE > 1'. std::exception_prt is only supported for
targets with always-lock-free atomics for int. This is a long-standing
issue in the libstdc++ and was finally fixed in GCC trunk r244051
[2][3] and will be available in GCC 7.0.

Any suggestions how to handle this build error?

1) Disable for the targets concerned and wait for GCC 7.0?
2) Backport the patch?

[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64735
[2] https://gcc.gnu.org/viewcvs/gcc/trunk/libstdc%2B%2B-v3/include/std/
future?view=log&pathrev=244051
[3] https://github.com/gcc-mirror/gcc/commit/c45be7f1aef92f2ea7363cbc46
27f943b83ca902

Best regards,
J?rg Krause