package/assimp: needs std::exception_ptr

Add dependency on !BR2_TOOLCHAIN_HAS_GCC_BUG_64735 to assure
std::exception_ptr support (the only in-tree assimp dependency
in package/qt5/qt53d is optional already).

Fixes:

  - http://autobuild.buildroot.net/results/0cc9cab2761591af57d6d6744a0dd61b7c60e935

  In file included from .../build/assimp-5.1.0/include/assimp/GenericProperty.h:52:0,
                   from .../build/assimp-5.1.0/code/Common/BaseProcess.h:46,
                   from .../build/assimp-5.1.0/code/Common/BaseProcess.cpp:44:
  .../build/assimp-5.1.0/include/assimp/Importer.hpp:522:11: error: 'exception_ptr' in namespace 'std' does not name a type
       const std::exception_ptr& GetException() const;
             ^

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/assimp/Config.in

@@ -3,6 +3,7 @@ config BR2_PACKAGE_ASSIMP
 	depends on BR2_INSTALL_LIBSTDCPP
 	depends on BR2_USE_WCHAR
 	depends on BR2_PACKAGE_LIBZLIB
+	depends on !BR2_TOOLCHAIN_HAS_GCC_BUG_64735 # exception_ptr
 	help
 	  Open Asset Import Library (assimp) is a portable Open Source
 	  library to import various well-known 3D model formats in a
@@ -18,3 +19,6 @@ comment "assimp needs a toolchain w/ C++, wchar"
 
 comment "assimp needs libzlib"
 	depends on !BR2_PACKAGE_LIBZLIB
+
+comment "assimp needs exception_ptr"
+	depends on BR2_TOOLCHAIN_HAS_GCC_BUG_64735