flex: Fix --noline option behavior

Option --noline or -L does not handled properly.
So generated code contains #line directives with
file absolute path and prevents to create
reproducible builds.

(From OE-Core rev: 0bf2cb7dc2123f220accf1542c2ae4c4b4b8275a)

Signed-off-by: Oleksiy Obitotskyy <oobitots@cisco.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/flex/flex/0001-Emit-no-line-directives-if-gen_line_dirs-is-false.patch

@@ -0,0 +1,32 @@
+From 440f3f55739468cd26e22f31871eca8cbbd53294 Mon Sep 17 00:00:00 2001
+From: Oleksiy Obitotskyy <oobitots@cisco.com>
+Date: Wed, 6 Jan 2021 06:12:14 -0800
+Subject: [PATCH] Emit no #line directives if gen_line_dirs is false
+
+If we set --noline we should not print line directives.
+But setting --noline means gen_line_dirs is false.
+
+Upstream-Status: Submitted
+Signed-off-by: Oleksiy Obitotskyy <oobitots@cisco.com>
+---
+ src/buf.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/src/buf.c b/src/buf.c
+index 185083c..4439e28 100644
+--- a/src/buf.c
++++ b/src/buf.c
+@@ -95,8 +95,8 @@ struct Buf *buf_linedir (struct Buf *buf, const char* filename, int lineno)
+     const char *src;
+     size_t tsz;
+ 
+-    if (gen_line_dirs)
+-	return buf;
++    if (!gen_line_dirs)
++        return buf;
+ 
+     tsz = strlen("#line \"\"\n")                +   /* constant parts */
+                2 * strlen (filename)            +   /* filename with possibly all backslashes escaped */
+-- 
+2.26.2.Cisco
+

meta/recipes-devtools/flex/flex_2.6.4.bb

@@ -16,6 +16,7 @@ SRC_URI = "https://github.com/westes/flex/releases/download/v${PV}/flex-${PV}.ta
            ${@bb.utils.contains('PTEST_ENABLED', '1', '', 'file://disable-tests.patch', d)} \
            file://0001-build-AC_USE_SYSTEM_EXTENSIONS-in-configure.ac.patch \
            file://check-funcs.patch \
+           file://0001-Emit-no-line-directives-if-gen_line_dirs-is-false.patch \
            "
 
 SRC_URI[md5sum] = "2882e3179748cc9f9c23ec593d6adc8d"