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, 54 insertions, 0 deletions

diff --git a/fs/ntfs/sysctl.c b/fs/ntfs/sysctl.c
new file mode 100644
index 000000000..8c5c1b7cd
--- /dev/null
+++ b/fs/ntfs/sysctl.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Code for sysctl handling in NTFS Linux kernel driver.
+ *
+ * Copyright (C) 1997 Martin von Löwis, Régis Duchesne
+ * Copyright (c) 2002-2005 Anton Altaparmakov
+ */
+
+#ifdef DEBUG
+
+#include <linux/module.h>
+
+#ifdef CONFIG_SYSCTL
+
+#include <linux/proc_fs.h>
+#include <linux/sysctl.h>
+
+#include "sysctl.h"
+#include "debug.h"
+
+/* Definition of the ntfs sysctl. */
+static const struct ctl_table ntfs_sysctls[] = {
+	{
+		.procname	= "ntfs-debug",
+		.data		= &debug_msgs,		/* Data pointer and size. */
+		.maxlen		= sizeof(debug_msgs),
+		.mode		= 0644,			/* Mode, proc handler. */
+		.proc_handler	= proc_dointvec
+	},
+};
+
+/* Storage for the sysctls header. */
+static struct ctl_table_header *sysctls_root_table;
+
+/*
+ * ntfs_sysctl - add or remove the debug sysctl
+ * @add:	add (1) or remove (0) the sysctl
+ *
+ * Add or remove the debug sysctl. Return 0 on success or -errno on error.
+ */
+int ntfs_sysctl(int add)
+{
+	if (add) {
+		sysctls_root_table = register_sysctl("fs/ntfs", ntfs_sysctls);
+		if (!sysctls_root_table)
+			return -ENOMEM;
+	} else {
+		unregister_sysctl_table(sysctls_root_table);
+		sysctls_root_table = NULL;
+	}
+	return 0;
+}
+#endif /* CONFIG_SYSCTL */
+#endif /* DEBUG */