gcc 7.3.0 compilation

[vondele]

src/config/sanitize.cpp: In function 'void fast_chess::config::sanitize(std::vector<fast_chess::EngineConfiguration>&)':
src/config/sanitize.cpp:98:26: error: 'std::filesystem' has not been declared
         auto p    = std::filesystem::path(configs[i].dir) / std::filesystem::path(configs[i].cmd);
                          ^~~~~~~~~~
src/config/sanitize.cpp:98:66: error: 'std::filesystem' has not been declared
         auto p    = std::filesystem::path(configs[i].dir) / std::filesystem::path(configs[i].cmd);
                                                                  ^~~~~~~~~~
src/config/sanitize.cpp:100:19: error: 'std::filesystem' has not been declared
         if (!std::filesystem::exists(path)) {
                   ^~~~~~~~~~
make[1]: *** [Makefile:133: tmp/src/config/sanitize.o] Error 1

[Disservin]

missing header include.. yikes

[vondele]

works with gcc 7.3.0 now