ruby: Use C11 _Alignof to define ALIGN_OF when possible

(From OE-Core rev: 5f01957c596673604516df42008b91551915967f)

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/ruby/ruby/0001-fiddle-Use-C11-_Alignof-to-define-ALIGN_OF-when-poss.patch

@@ -0,0 +1,52 @@
+From 6b3c202b46b9312c5bb0789145f13d8086e70948 Mon Sep 17 00:00:00 2001
+From: Khem Raj <raj.khem@gmail.com>
+Date: Sun, 15 Jan 2023 02:34:17 -0800
+Subject: [PATCH] fiddle: Use C11 _Alignof to define ALIGN_OF when possible
+
+WG14 N2350 made very clear that it is an UB having type definitions
+within "offsetof" [1]. This patch enhances the implementation of macro
+ALIGN_OF to use builtin "_Alignof" to avoid undefined behavior
+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 compiler versions
+
+[1] https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm
+[2] https://reviews.llvm.org/D133574
+
+Upstream-Status: Submitted [https://ml.ruby-lang.org/mailman3/hyperkitty/list/ruby-core@ml.ruby-lang.org/thread/DLES4EPPXSPCHQMWJPPWMWXXS42AVPFA/]
+Signed-off-by: Khem Raj <raj.khem@gmail.com>
+---
+ ext/fiddle/fiddle.h | 12 +++++++++++-
+ 1 file changed, 11 insertions(+), 1 deletion(-)
+
+diff --git a/ext/fiddle/fiddle.h b/ext/fiddle/fiddle.h
+index 10eb9ce..ffb395e 100644
+--- a/ext/fiddle/fiddle.h
++++ b/ext/fiddle/fiddle.h
+@@ -196,7 +196,17 @@
+ #endif
+ #define TYPE_UINTPTR_T (-TYPE_INTPTR_T)
+ 
+-#define ALIGN_OF(type) offsetof(struct {char align_c; type align_x;}, align_x)
++/* 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 ALIGN_OF(type) offsetof(struct {char align_c; type align_x;}, align_x)
++#else
++# define ALIGN_OF(type) _Alignof(type)
++#endif
+ 
+ #define ALIGN_VOIDP  ALIGN_OF(void*)
+ #define ALIGN_CHAR   ALIGN_OF(char)
+-- 
+2.39.0
+

meta/recipes-devtools/ruby/ruby_3.2.0.bb

@@ -30,6 +30,7 @@ SRC_URI = "http://cache.ruby-lang.org/pub/ruby/${SHRT_VER}/ruby-${PV}.tar.gz \
            file://0005-Mark-Gemspec-reproducible-change-fixing-784225-too.patch \
            file://0006-Make-gemspecs-reproducible.patch \
            file://0001-vm_dump.c-Define-REG_S1-and-REG_S2-for-musl-riscv.patch \
+           file://0001-fiddle-Use-C11-_Alignof-to-define-ALIGN_OF-when-poss.patch \
            "
 UPSTREAM_CHECK_URI = "https://www.ruby-lang.org/en/downloads/"