"g++-6"   -fvisibility-inlines-hidden -std=gnu++11 -fPIC -m64 -pthread -O0 -fno-inline -Wall -fvisibility=hidden  -DBOOST_ALL_NO_LIB=1 -DBOOST_CHARCONV_DYN_LINK=1 -DBOOST_CHARCONV_NO_LIB=1 -DBOOST_COBALT_USE_STD_PMR=1   -I".." -I"/var/boost/run/boost_root/libs/assert/include" -I"/var/boost/run/boost_root/libs/charconv/include" -I"/var/boost/run/boost_root/libs/core/include" -I"/var/boost/run/boost_root/libs/throw_exception/include"  -c -o "/var/boost/run/results/boost/bin.v2/libs/parser/test/hl.test/gcc-6~gnu11/debug/x86_64/debug-symbols-off/threading-multi/visibility-hidden/hl.o" "../libs/parser/test/hl.cpp"

../libs/parser/test/hl.cpp:11:20: fatal error: optional: No such file or directory
 #include <optional>
                    ^
compilation terminated.