-m4_version_prereq([2.63],, [
-
-# _AC_ARG_VAR_VALIDATE
-# --------------------
-# The code is the same as autoconf 2.59, but with a more lenient check
-# on precious variables and an output of pwd that have been added in
-# autoconf 2.62.
-m4_define([_AC_ARG_VAR_VALIDATE],
-[m4_divert_text([INIT_PREPARE],
-[# Check that the precious variables saved in the cache have kept the same
-# value.
-ac_cache_corrupted=false
-for ac_var in `(set) 2>&1 |
- sed -n 's/^ac_env_\([[a-zA-Z_0-9]]*\)_set=.*/\1/p'`; do
- eval ac_old_set=\$ac_cv_env_${ac_var}_set
- eval ac_new_set=\$ac_env_${ac_var}_set
- eval ac_old_val="\$ac_cv_env_${ac_var}_value"
- eval ac_new_val="\$ac_env_${ac_var}_value"
- case $ac_old_set,$ac_new_set in
- set,)
- AS_MESSAGE([error: `$ac_var' was set to `$ac_old_val' in the previous run], 2)
- ac_cache_corrupted=: ;;
- ,set)
- AS_MESSAGE([error: `$ac_var' was not set in the previous run], 2)
- ac_cache_corrupted=: ;;
- ,);;
- *)
- if test "x$ac_old_val" != "x$ac_new_val"; then
- # differences in whitespace do not lead to failure.
- ac_old_val_w=`echo x $ac_old_val`
- ac_new_val_w=`echo x $ac_new_val`
- if test "$ac_old_val_w" != "$ac_new_val_w"; then
- AS_MESSAGE([error: `$ac_var' has changed since the previous run:], 2)
- ac_cache_corrupted=:
- else
- AS_MESSAGE([warning: ignoring whitespace changes in `$ac_var' since the previous run:], 2)
- eval $ac_var=\$ac_old_val
- fi
- AS_MESSAGE([ former value: `$ac_old_val'], 2)
- AS_MESSAGE([ current value: `$ac_new_val'], 2)
- fi;;
- esac
- # Pass precious variables to config.status.
- if test "$ac_new_set" = set; then
- case $ac_new_val in
-dnl If you change this globbing pattern, test it on an old shell --
-dnl it's sensitive. Putting any kind of quote in it causes syntax errors.
-[ *" "*|*" "*|*[\[\]\~\#\$\^\&\*\(\)\{\}\\\|\;\<\>\?\"\']*)]
- ac_arg=$ac_var=`echo "$ac_new_val" | sed "s/'/'\\\\\\\\''/g"` ;;
- *) ac_arg=$ac_var=$ac_new_val ;;
- esac
- case " $ac_configure_args " in
- *" '$ac_arg' "*) ;; # Avoid dups. Use of quotes ensures accuracy.
- *) ac_configure_args="$ac_configure_args '$ac_arg'" ;;
- esac
- fi
-done
-if $ac_cache_corrupted; then
- AS_MESSAGE([error: in `$ac_pwd':], 2)
- AS_MESSAGE([error: changes in the environment can compromise the build], 2)
- AS_ERROR([run `make distclean' and/or `rm $cache_file' and start over])
-fi])dnl
-])# _AC_ARG_VAR_VALIDATE
-])
-
-m4_version_prereq([2.63],, [
-
-# AC_MSG_FAILURE(ERROR, [EXIT-STATUS = 1])
-# ----------------------------------------
-# This is the same code as in 2.59 and 2.61, except it also outputs pwd.
-m4_define([AC_MSG_FAILURE],
-[{ AS_MESSAGE([error: in `$ac_pwd':], 2)
-AC_MSG_ERROR([$1
-See `config.log' for more details.], [$2]); }])
-])
-])
+dnl If flex/lex are not found, the top level configure sets LEX to
+dnl "/path_to/missing flex". When AC_PROG_LEX tries to find the flex
+dnl output file, it calls $LEX to do so, but the current lightweight
+dnl "missing" won't create a file. This results in an error.
+dnl Avoid calling the bulk of AC_PROG_LEX when $LEX is "missing".
+AC_DEFUN_ONCE([AC_PROG_LEX],
+[AC_CHECK_PROGS(LEX, flex lex, :)
+case "$LEX" in
+ :|*"missing "*) ;;
+ *) _AC_PROG_LEX_YYTEXT_DECL ;;
+esac])