string(REGEX MATCH "[0-9]+[.]+[0-9]+[.]+[0-9]+" FLEX_VERSION "${FLEX_VERSION}")
string(REGEX MATCH "^[0-9]+" FLEX_MAJOR_VERSION "${FLEX_VERSION}")
string(REGEX MATCH "[0-9]+[.]+[0-9]+$" FLEX_VERSION "${FLEX_VERSION}")
string(REGEX MATCH "[0-9]+[.]+[0-9]+[.]+[0-9]+" FLEX_VERSION "${FLEX_VERSION}")
string(REGEX MATCH "^[0-9]+" FLEX_MAJOR_VERSION "${FLEX_VERSION}")
string(REGEX MATCH "[0-9]+[.]+[0-9]+$" FLEX_VERSION "${FLEX_VERSION}")