src/marpaESLIF.c: add missing errno set, say that a NULL string must not have size > 0 [ci skip]
src/marpaESLIF.c: add missing errno set, say that a NULL string must not have size > 0 [ci skip]

jddurand/c-marpaESLIF,jddurand/c-marpaESLIF,jddurand/c-marpaESLIF,jddurand/c-marpaESLIF,jddurand/c-marpaESLIF