CXX ?= g++-10
CXXFLAGS := \
--std=c++2a --all-warnings --extra-warnings --pedantic-errors \
-Werror -Wshadow -Wfloat-equal -Weffc++ -Wdelete-non-virtual-dtor \
-Warray-bounds -Wattribute-alias -Wformat-overflow -Wformat-truncation \
-Wmissing-attributes -Wstringop-truncation \
-Wdeprecated-copy -Wclass-conversion \
-O1