Missing include when compiling with GNU 13 compiler

[AxelKrypton]

According to GNU compiler documentation about new aspects in GNU 13, the <cstdint> header providing fixed width integer types has to be explicitly included in the new version. Indeed using the testing framework in an external project and hence having to include vir/test.h breaks down compilation with GNU 13, because std::uint8_t type is not found any more. This is used here:

virtest/vir/test.h

Line 779 in 95a85e2

const auto bytes = reinterpret_cast<const std::uint8_t *>(&x);

Adding the missing #include <cstdint> should fix the problem.