build: replace `AM_PROG_LEX` with `AC_PROG_LEX`

`AM_PROG_LEX` calls `AC_PROG_LEX` with no arguments, but this usage is
deprecated.  The only difference between `AM_PROG_LEX` and `AC_PROG_LEX`
is that the former defines `$LEX` as "./build-aux/missing lex" if no lex
is found to ensure a useful error is reported when make is run.  How-
ever, the configure script checks that we have a working lex and exits
with an error if none is available, so `$LEX` will never be called and
we can replace `AM_PROG_LEX` with `AC_PROG_LEX`.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

0 files changed, 0 insertions, 0 deletions