opkg: Define alignof using _Alignof when using C11 or newer

(From OE-Core rev: 582a09b54d6b78706f8834a4f616d4ea97feceb3)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/opkg/opkg/0001-Define-alignof-using-_Alignof-when-using-C11-or-newe.patch

@@ -0,0 +1,51 @@
+From 4089affd371e6d62dd8c1e57b344f8cc329005ea Mon Sep 17 00:00:00 2001
+From: Khem Raj <raj.khem@gmail.com>
+Date: Sat, 14 Jan 2023 23:11:08 -0800
+Subject: [PATCH] Define alignof using _Alignof when using C11 or newer
+
+WG14 N2350 made very clear that it is an UB having type definitions
+within "offsetof" [1]. This patch enhances the implementation of macro
+alignof_slot to use builtin "_Alignof" to avoid undefined behavior on
+when using std=c11 or newer
+
+clang 16+ has started to flag this [2]
+
+Fixes build when using -std >= gnu11 and using clang16+
+
+Older compilers gcc < 4.9 or clang < 8 has buggy _Alignof even though it
+may support C11, exclude those compilers too
+
+[1] https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm
+[2] https://reviews.llvm.org/D133574
+
+Upstream-Status: Submitted [https://groups.google.com/g/opkg-devel/c/gjcQPZgT_jI]
+Signed-off-by: Khem Raj <raj.khem@gmail.com>
+---
+ libopkg/md5.c | 10 ++++++++++
+ 1 file changed, 10 insertions(+)
+
+diff --git a/libopkg/md5.c b/libopkg/md5.c
+index 981b9b8..ccb645e 100644
+--- a/libopkg/md5.c
++++ b/libopkg/md5.c
+@@ -237,7 +237,17 @@ void md5_process_bytes(const void *buffer, size_t len, struct md5_ctx *ctx)
+     /* Process available complete blocks.  */
+     if (len >= 64) {
+ #if !_STRING_ARCH_unaligned
++/* GCC releases before GCC 4.9 had a bug in _Alignof.  See GCC bug 52023
++   <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52023>.
++   clang versions < 8.0.0 have the same bug.  */
++#if (!defined __STDC_VERSION__ || __STDC_VERSION__ < 201112 \
++     || (defined __GNUC__ && __GNUC__ < 4 + (__GNUC_MINOR__ < 9) \
++         && !defined __clang__) \
++     || (defined __clang__ && __clang_major__ < 8))
+ #define alignof(type) offsetof (struct { char c; type x; }, x)
++#else
++#define alignof(type) _Alignof(type)
++#endif
+ #define UNALIGNED_P(p) (((size_t) p) % alignof (uint32_t) != 0)
+         if (UNALIGNED_P(buffer))
+             while (len > 64) {
+-- 
+2.39.0
+

meta/recipes-devtools/opkg/opkg_0.6.1.bb

@@ -16,6 +16,7 @@ SRC_URI = "http://downloads.yoctoproject.org/releases/${BPN}/${BPN}-${PV}.tar.gz
            file://opkg.conf \
            file://0001-opkg_conf-create-opkg.lock-in-run-instead-of-var-run.patch \
            file://0002-opkg-key-remove-no-options-flag-from-gpg-calls.patch \
+           file://0001-Define-alignof-using-_Alignof-when-using-C11-or-newe.patch \
            file://run-ptest \
 "