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, 26 insertions, 0 deletions

diff --git a/scripts/modules-check.sh b/scripts/modules-check.sh
new file mode 100755
index 000000000..4c8da90de
--- /dev/null
+++ b/scripts/modules-check.sh
@@ -0,0 +1,26 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+set -e
+
+if [ $# != 1 ]; then
+	echo "Usage: $0 <modules.order>" >& 2
+	exit 1
+fi
+
+exit_code=0
+
+# Check uniqueness of module names
+check_same_name_modules()
+{
+	for m in $(sed 's:.*/::' "$1" | sort | uniq -d)
+	do
+		echo "error: the following would cause module name conflict:" >&2
+		sed -n "/\/$m/s:^\(.*\)\.o\$:  \1.ko:p" "$1" >&2
+		exit_code=1
+	done
+}
+
+check_same_name_modules "$1"
+
+exit $exit_code