package/libodb: fix build with gcc 11

package/libodb: fix build with gcc 11

GCC 11 defaults to C++17. Fix the following build failure with gcc 11:

In file included from details/shared-ptr/base.cxx:5:
../odb/details/shared-ptr/base.hxx:38:49: error: ISO C++17 does not allow dynamic exception specifications
   38 | operator new (std::size_t, odb::details::share) throw (std::bad_alloc);
      |                                                 ^~~~~

Fixes:
 - http://autobuild.buildroot.org/results/cfd5f92f0aa923815edba5fbfcd5b7b312d9d40e

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>