From ba01560b869bd213159bdaaaf22239372d94827f Mon Sep 17 00:00:00 2001
From: vasko-110 <v.o.ivanishchev@gmail.com>
Date: Tue, 8 Sep 2026 13:06:54 +0300
Subject: [PATCH] debugging: define ElfW when the target has no <link.h>

ABSL_HAVE_ELF_MEM_IMAGE is enabled for every __ELF__ target except an
explicit deny-list, and the header then includes <link.h>
unconditionally. __ELF__ describes the object format, not the presence of
a dynamic loader: bare-metal ELF toolchains produce ELF objects and ship
no <link.h>. On arm-none-eabi with newlib the include is reached and the
build fails with a fatal error.

newlib does provide <elf.h>, so include that when <link.h> is missing and
define ElfW from the target's pointer size. This generalizes the existing
FreeBSD case, which already defines ElfW itself.

Platforms that do have <link.h> are unaffected: it defines ElfW, so the
fallback block is skipped.
---
 absl/debugging/internal/elf_mem_image.h | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/absl/debugging/internal/elf_mem_image.h b/absl/debugging/internal/elf_mem_image.h
index 4d31a474cfd..f24aa26f2ac 100644
--- a/absl/debugging/internal/elf_mem_image.h
+++ b/absl/debugging/internal/elf_mem_image.h
@@ -42,10 +42,20 @@
 
 #ifdef ABSL_HAVE_ELF_MEM_IMAGE
 
+#if __has_include(<link.h>)
 #include <link.h>  // for ElfW
+#else
+#include <elf.h>
+#endif
 
-#if defined(__FreeBSD__) && !defined(ElfW)
-#define ElfW(x) __ElfN(x)
+#ifndef ElfW
+#if defined(__FreeBSD__)
+#define ElfW(type) __ElfN(type)
+#elif __SIZEOF_POINTER__ == 8
+#define ElfW(type) Elf64_##type
+#else
+#define ElfW(type) Elf32_##type
+#endif
 #endif
 
 namespace absl {