The code to detect [f]lex in configure.ac uses a syntax not coherent with AC_PREREQ
The current content of configure.ac
starts with AC_PREREQ([2.69])
and further contains AC_PROG_LEX(yywrap)
.
However, the official doc substantially differs from 2.69 to 2.70, namely the possibility of providing an argument to AC_PROG_LEX
seems to be introduced with 2.70 ("Prior to Autoconf 2.70, AC_PROG_LEX did not take any arguments, and its behavior was different")
I am not understanding what they are talking about in the doc, but the 2.69 seemed to say that the snippet defining LEX="$SHELL $missing_dir/missing flex"
should be used only if a function yywrap
is provided or a %noyywrap
statement is present in the code. Yet, we do have a %noyywrap
statement in our lexers. Therefore, it seems to me that we should rather pass the option noyywrap
to AC_PROG_LEX
. Notice however that the 2.70 states the things about the above-mentioned snippet differently, and I would not necessarily have drawn the same conclusion, would I have read only the 2.70 and not the 2.69.
Anyway, my feeling is that it is worth taking the time of trying to understand this mess.