unit test framework issue with Ubuntu 22

[patcmorneau]

OpenSidescan/test/catch.hpp:10717:58: error: call to non-‘constexpr’ function ‘long int sysconf(int)’
10717 |     static constexpr std::size_t sigStackSize = 32768 >= MINSIGSTKSZ ? 32768 : MINSIGSTKSZ;