[project @ 2001-05-27 05:00:08 by sof]
'flex' or 'lex' is required to compile up fptools/ (e.g., reqd in glafp-utils/sgmlverb). autoconf's standard macro AC_PROG_LEX just defaults to 'lex' if 'flex' isn't found, but doesn't actually check whether 'lex' is available along PATH. Added AC_PROG_LEX_STRICT, which extends AC_PROG_LEX by checking for the presence of 'lex' if 'flex' isn't found. It bails out with an error message if 'lex' cannot be found.