Fix CVE-2016-6354 (Buffer overflow in generated code (yy_get_next_buffer).

https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-6354
https://security-tracker.debian.org/tracker/CVE-2016-6354

Patch copied from upstream source repository:
https://github.com/westes/flex/commit/a5cbe929ac3255d371e698f62dc256afe7006466

From a5cbe929ac3255d371e698f62dc256afe7006466 Mon Sep 17 00:00:00 2001
From: Will Estes <westes575@gmail.com>
Date: Sat, 27 Feb 2016 11:56:05 -0500
Subject: [PATCH] Fixed incorrect integer type

---
 src/flex.skl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/flex.skl b/src/flex.skl
index 36a526a..64f853d 100644
--- a/src/flex.skl
+++ b/src/flex.skl
@@ -1703,7 +1703,7 @@ int yyFlexLexer::yy_get_next_buffer()
 
 	else
 		{
-			yy_size_t num_to_read =
+			int num_to_read =
 			YY_CURRENT_BUFFER_LVALUE->yy_buf_size - number_to_move - 1;
 
 		while ( num_to_read <= 0 )
