From 3c4b6f8165e785f602e576a51f645f463f01c836 Mon Sep 17 00:00:00 2001
From: Ramakrishnan Muthukrishnan <address@hidden>
Date: Fri, 19 Nov 2010 22:48:13 +0530
Subject: [PATCH] check for `flex' in configure.ac

* configure.ac: check for the presence of `GNU flex' and flag an error
  if it is not found.
* libguile/Makefile.am: use the LEX variable set by configure to invoke
  `GNU flex'.
---
 configure.ac         |    6 ++++++
 libguile/Makefile.am |    2 +-
 2 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/configure.ac b/configure.ac
index 3446992..a684fb8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -82,6 +82,12 @@ if test "x$HAVE_LIBLTDL" != "xyes"; then
   AC_MSG_ERROR([GNU libltdl (Libtool) not found, see README.])
 fi
 
+AC_PROG_LEX
+if test "x$LEX" != xflex; then
+  AC_MSG_ERROR([GNU flex not found.])
+fi
+
+
 AC_CHECK_PROG(have_makeinfo, makeinfo, yes, no)
 AM_CONDITIONAL(HAVE_MAKEINFO, test "$have_makeinfo" = yes)
 
diff --git a/libguile/Makefile.am b/libguile/Makefile.am
index 55a9764..41bc090 100644
--- a/libguile/Makefile.am
+++ b/libguile/Makefile.am
@@ -695,7 +695,7 @@ guile-procedures.txt: guile-procedures.texi
 endif
 
 c-tokenize.c: c-tokenize.lex
-	flex -t $(srcdir)/c-tokenize.lex > $@ || { rm $@; false; }
+	$(LEX) -t $(srcdir)/c-tokenize.lex > $@ || { rm $@; false; }
 
 schemelibdir = $(pkgdatadir)/$(GUILE_EFFECTIVE_VERSION)
 schemelib_DATA = guile-procedures.txt
-- 
1.7.2.3