From 5d71e9ffb98e3ed719b5bf7ed2c52d8b6f26e65f Mon Sep 17 00:00:00 2001
From: Explorer09 <explorer09@gmail.com>
Date: Mon, 31 Oct 2016 21:15:41 +0800
Subject: [PATCH] build: Add --disable-libfl configure option.

Disabling libfl is useful when building flex for a cross-toolchain.

Fixes: GH-99
---
 configure.ac    |  6 ++++++
 src/Makefile.am | 16 ++++++++--------
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/configure.ac b/configure.ac
index 75fa9d5..362740a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -60,6 +60,12 @@ AC_ARG_ENABLE([warnings],
 
 AC_SUBST([WARNINGFLAGS])
 
+AC_ARG_ENABLE([libfl],
+  [AS_HELP_STRING([--disable-libfl],
+                  [do not build -lfl runtime support library])],
+  [], [enable_libfl=yes])
+AM_CONDITIONAL([ENABLE_LIBFL], [test "$enable_libfl" = yes])
+
 AC_PATH_PROG([BISON], bison, no)
 AS_IF([test "$BISON" != no],[],
 	[ AC_SUBST([BISON], [\${top_srcdir}/build-aux/missing bison])
diff --git a/src/Makefile.am b/src/Makefile.am
index ffc9d2e..3abc1e4 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -7,8 +7,14 @@ m4 = @M4@
 
 bin_PROGRAMS = flex
 noinst_PROGRAMS = stage1flex
-lib_LTLIBRARIES = \
-	libfl.la
+
+if ENABLE_LIBFL
+lib_LTLIBRARIES = libfl.la
+libfl_la_SOURCES = \
+	libmain.c \
+	libyywrap.c
+libfl_la_LDFLAGS = -version-info @SHARED_VERSION_INFO@
+endif
 
 stage1flex_SOURCES = \
 	scan.l \
@@ -55,12 +61,6 @@ COMMON_SOURCES = \
 
 LDADD = ../lib/libcompat.la @LIBINTL@
 
-libfl_la_SOURCES = \
-	libmain.c \
-	libyywrap.c
-
-libfl_la_LDFLAGS = -version-info @SHARED_VERSION_INFO@
-
 include_HEADERS = \
 	FlexLexer.h
 
-- 
2.40.0