[source] flex: update to 2.6.4 (FS#809)

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/aeeb2faf88f6042aabd9fd9e9b40b30fdfe56398

commit aeeb2faf88f6042aabd9fd9e9b40b30fdfe56398
Author: Eric Luehrsen <ericluehrsen at hotmail.com>
AuthorDate: Fri May 26 00:02:47 2017 -0400

    flex: update to 2.6.4 (FS#809)
    
    flex 2.6.3 has a bug which fails code generation and compile of some packages
    
    Signed-off-by: Eric Luehrsen <ericluehrsen at hotmail.com>
---
 tools/flex/Makefile | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/flex/Makefile b/tools/flex/Makefile
index f170be5..760721a 100644
--- a/tools/flex/Makefile
+++ b/tools/flex/Makefile
@@ -1,4 +1,4 @@
-# 
+#
 # Copyright (C) 2008-2016 OpenWrt.org
 #
 # This is free software, licensed under the GNU General Public License v2.
@@ -7,11 +7,11 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=flex
-PKG_VERSION:=2.6.3
+PKG_VERSION:=2.6.4
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=https://github.com/westes/flex/releases/download/v$(PKG_VERSION)/
-PKG_HASH:=68b2742233e747c462f781462a2a1e299dc6207401dac8f0bbb316f48565c2aa
+PKG_HASH:=e87aae032bf07c26f85ac0ed3250998c37621d95f8bd748b31f15b33c45ee995
 
 HOST_BUILD_PARALLEL:=1