objtool: Validate disassembler headers in libopcodes probegrafted

commit 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries")
tested for libopcodes availability by linking a test snippet with a forward
declaration of disassemble_init_for_target().

However, testing symbol linkage with an extern declaration only verifies
the presence of the library (.so/.a) and bypasses checking for development
headers (binutils-dev). On systems where libopcodes is present without
development headers installed, the probe succeeds, enabling BUILD_DISAS.
Subsequent compilation of objtool then fails:

  fatal error: 'bfd.h' file not found
    113 | #include <bfd.h>

Additionally, the probe invokes $(HOSTCC) without $(HOSTCFLAGS), ignoring
any sysroot or include flags specified for the host compiler.

Fix this by including <bfd.h> and <dis-asm.h> directly in the test snippet,
passing $(HOSTCFLAGS) so host compiler options are respected, and defining
PACKAGE="objtool" to satisfy the configuration check in <bfd.h>.

Fixes: 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries")
Fixes: 436326bc525d ("objtool: fix build failure due to missing libopcodes check")
Reported-by: Alice Ryhl <aliceryhl@google.com>
Assisted-by: Antigravity:Gemini-Next
Signed-off-by: Ulises Mendez Martinez <umendez@google.com>
Link: https://patch.msgid.link/20260904150710.2997558-1-umendez@google.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/Documentation/dev-tools/index.rst b/Documentation/dev-tools/index.rst
new file mode 100644
index 000000000..59cbb77b3
--- /dev/null
+++ b/Documentation/dev-tools/index.rst
@@ -0,0 +1,42 @@
+================================
+Development tools for the kernel
+================================
+
+This document is a collection of documents about development tools that can
+be used to work on the kernel. For now, the documents have been pulled
+together without any significant effort to integrate them into a coherent
+whole; patches welcome!
+
+A brief overview of testing-specific tools can be found in
+Documentation/dev-tools/testing-overview.rst
+
+Tools that are specific to debugging can be found in
+Documentation/process/debugging/index.rst
+
+.. toctree::
+   :caption: Table of contents
+   :maxdepth: 2
+
+   testing-overview
+   checkpatch
+   clang-format
+   coccinelle
+   context-analysis
+   sparse
+   kcov
+   gcov
+   kasan
+   kmsan
+   ubsan
+   kmemleak
+   kcsan
+   lkmm/index
+   kfence
+   kselftest
+   kunit/index
+   ktap
+   checkuapi
+   gpio-sloppy-logic-analyzer
+   autofdo
+   propeller
+   container