package/libodb-pqsql: fix build with gcc 11

package/libodb-pqsql: fix build with gcc 11

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

configure:13698: checking for libodb
configure:13772: /tmp/instance-1/output-1/host/bin/arm-buildroot-linux-gnueabihf-g++ -c -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -Os -g0 -D_FORTIFY_SOURCE=2 -D_REENTRANT  -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 conftest.cpp >&5
In file included from /tmp/instance-1/output-1/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/odb/exception.hxx:15,
                 from conftest.cpp:26:
/tmp/instance-1/output-1/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/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/73b06d7f923e5a7294377951f212b89b6cb0946a

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