Author: Perry Lorier <isomer@undernet.org>

[ircu2.10.12-pk.git] / configure.in

diff --git a/configure.in b/configure.in
index 88ec8c71f848bd8de6622551009f10f8f35d9da4..8af70805fcb2abd472579d699ef3aaeb81e5e71d 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -142,16 +142,18 @@ AC_PATH_PROGS(SHPROG, sh, /bin/sh)
 
 dnl (F)LEX - needed for the new conf file parser
 AC_PROG_LEX
-if test -x "$LEX"
-then 
+dnl The autoconf docs say $LEX defaults to 'lex'.  They lie.
+if test "$LEX" = ":" ; then
   AC_MSG_ERROR([Cannot find flex.])
+elif echo "" | $LEX -V -v --version > /dev/null 2>&1 ; then
+  :
+else
+  AC_MSG_ERROR([Cannot use $LEX as flex.])
 fi
 
-if test -z "$LEXLIB"
-then
-  AC_MSG_FAILURE([
-  Cannot find a library with yywrap() in, but flex was found.  
-  It's possible the compiler you're using ($CC) is incompatible with the 
+if test -z "$LEXLIB" ; then
+  AC_MSG_FAILURE([Cannot find a library with yywrap() in, but flex was found.
+  It's possible the compiler you're using ($CC) is incompatible with the
   installed library.])
 fi
 
@@ -159,9 +161,15 @@ LIBS="$LEXLIB $LIBS"
 
 dnl YACC - ditto
 AC_PROG_YACC
-if test -z "$YACC"
-then
+dnl The autoconf docs say $YACC defaults to 'yacc'.  This seems to be true,
+dnl but judging from AC_PROG_LEX, it may not stay true.
+if test "$YACC" = ":" ; then
   AC_MSG_ERROR([Cannot find yacc.])
+elif echo "" | $YACC -V -v --version > /dev/null 2>&1 ; then
+  :
+else
+dnl byacc does not seem to have any way to test for workingness, so only warn.
+  AC_MSG_WARN([$YACC may not work as yacc.])
 fi