sys-devel/flex: backport "config.h" fix too

We already have the patch to config.h/configure.ac backported
but we don't have the fix to actually *use* config.h everywhere,
and clearly from bug #705800 it wasn't sufficient to just backport
it (for reasons covered in the bug & upstream bug).

Bug: https://bugs.gentoo.org/628744
Bug: https://bugs.gentoo.org/705800
Signed-off-by: Sam James <sam@gentoo.org>

1 files changed, 50 insertions, 0 deletions

diff --git a/sys-devel/flex/files/flex-2.6.4-implicit-func-decl.patch b/sys-devel/flex/files/flex-2.6.4-implicit-func-decl.patch
new file mode 100644
index 000000000000..1900ae0529b9
--- /dev/null
+++ b/sys-devel/flex/files/flex-2.6.4-implicit-func-decl.patch
@@ -0,0 +1,50 @@
+https://github.com/westes/flex/commit/4b5111d9772b5c160340ca96f08d30d7f6db5cda
+https://github.com/westes/flex/issues/436
+https://bugs.gentoo.org/705800
+https://developers.redhat.com/blog/2019/04/22/implicit-function-declarations-flexs-use-of-reallocarray
+
+From 4b5111d9772b5c160340ca96f08d30d7f6db5cda Mon Sep 17 00:00:00 2001
+From: Explorer09 <explorer09@gmail.com>
+Date: Mon, 4 Sep 2017 08:28:53 +0800
+Subject: [PATCH] scanner: Include flexdef.h at %top block of scan.l
+
+config.h may define macros that alter the API of the standard library
+funtions, and so it should be included before any other standard
+header, even before the skeleton's standard header inclusion.
+
+For example: config.h may #define _GNU_SOURCE that would expose the
+reallocarray() prototype from <stdlib.h> on glibc 2.26+ systems. If we
+include <stdlib.h> before config.h, reallocarray() would not be
+available for use in lex file since the second include doesn't help
+due to header guard.
+
+For now our config.h might `#define malloc rpl_malloc` -- this
+substitution must work before including stdlib.h, or else the compiler
+will complain about missing prototypes, and may result in incorrect
+code in scan.l (gcc warning: return makes pointer from integer without
+a cast [-Wint-conversion]).
+
+Fixes #247.
+--- a/src/scan.l
++++ b/src/scan.l
+@@ -1,5 +1,11 @@
+ /* scan.l - scanner for flex input -*-C-*- */
+ 
++%top{
++/* flexdef.h includes config.h, which may contain macros that alter the API */
++/* of libc functions. Must include first before any libc header. */
++#include "flexdef.h"
++}
++
+ %{
+ /*  Copyright (c) 1990 The Regents of the University of California. */
+ /*  All rights reserved. */
+@@ -32,7 +38,6 @@
+ /*  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR */
+ /*  PURPOSE. */
+ 
+-#include "flexdef.h"
+ #include "parse.h"
+ extern bool tablesverify, tablesext;
+ extern int trlcontxt; /* Set in  parse.y for each rule. */
+