[Buildroot] [PATCH] boost: module context affected by GCC bug 64735

[Jörg Krause]

Building boosts module context is affected by GCC bug 64735 [1]:

```
./boost/context/execution_context_v2.hpp:298:31: error: 'exception_ptr' is not a member of 'std'
     auto p = std::make_tuple( std::exception_ptr{}, std::move( data) );
```

This is because `exception_ptr` from libstdc++ is not available for
architectures not supporting always lock-free atomic ints.

Note, that this bug is fixed in GCC 7.

Fixes:
http://autobuild.buildroot.net/results/f4e/f4e8a3727f19f7df4a1c45efe3603422fafd4af5/

[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64735

Signed-off-by: Jörg Krause <joerg.krause at embedded.rocks>
---
 package/boost/Config.in | 1 +
 1 file changed, 1 insertion(+)

diff --git a/package/boost/Config.in b/package/boost/Config.in
index f0a2385706..50d0ff8e01 100644
--- a/package/boost/Config.in
+++ b/package/boost/Config.in
@@ -67,6 +67,7 @@ config BR2_PACKAGE_BOOST_CONTEXT
 	bool "boost-context"
 	depends on ((BR2_arm || BR2_armeb) && BR2_ARM_CPU_HAS_ARM) || \
 		BR2_i386 || BR2_mips || BR2_mipsel || BR2_powerpc || BR2_x86_64
+	depends on !BR2_TOOLCHAIN_HAS_GCC_BUG_64735
 
 config BR2_PACKAGE_BOOST_COROUTINE
 	bool "boost-coroutine"
-- 
2.13.1