Bug#878496: python-escript FTBFS on 32bit with gcc 7

[Adrian Bunk]

Source: python-escript
Version: 5.0-4
Severity: serious

https://buildd.debian.org/status/package.php?p=python-escript&suite=sid

...
escriptcore/src/DataFactory.cpp: In function 'escript::Data escript::VectorFromObj(boost::python::api::object, const escript::FunctionSpace&, bool)':
escriptcore/src/DataFactory.cpp:49:41: error: '*((void*)&<anonymous> +12)' may be used uninitialized in this function [-Werror=maybe-uninitialized]
         double v = bp::extract<double>(o);
                                         ^
escriptcore/src/DataFactory.cpp: In function 'escript::Data escript::TensorFromObj(boost::python::api::object, const escript::FunctionSpace&, bool)':
escriptcore/src/DataFactory.cpp:75:41: error: '*((void*)&<anonymous> +12)' may be used uninitialized in this function [-Werror=maybe-uninitialized]
         double v = bp::extract<double>(o);
                                         ^
escriptcore/src/DataFactory.cpp: In function 'escript::Data escript::Tensor3FromObj(boost::python::api::object, const escript::FunctionSpace&, bool)':
escriptcore/src/DataFactory.cpp:99:41: error: '*((void*)&<anonymous> +12)' may be used uninitialized in this function [-Werror=maybe-uninitialized]
         double v = bp::extract<double>(o);
                                         ^
escriptcore/src/DataFactory.cpp: In function 'escript::Data escript::Tensor4FromObj(boost::python::api::object, const escript::FunctionSpace&, bool)':
escriptcore/src/DataFactory.cpp:123:41: error: '*((void*)&<anonymous> +12)' may be used uninitialized in this function [-Werror=maybe-uninitialized]
         double v = bp::extract<double>(o);
                                         ^
cc1plus: all warnings being treated as errors
scons: *** [debian/tmp2/posix/escriptcore/src/DataFactory.os] Error 1
scons: building terminated because of errors.