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, 43 insertions, 0 deletions

diff --git a/arch/powerpc/boot/ofconsole.c b/arch/powerpc/boot/ofconsole.c
new file mode 100644
index 000000000..8eb0f1c45
--- /dev/null
+++ b/arch/powerpc/boot/ofconsole.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * OF console routines
+ *
+ * Copyright (C) Paul Mackerras 1997.
+ */
+#include <stddef.h>
+#include "types.h"
+#include "elf.h"
+#include "string.h"
+#include "stdio.h"
+#include "page.h"
+#include "ops.h"
+
+#include "of.h"
+
+static unsigned int of_stdout_handle;
+
+static int of_console_open(void)
+{
+	void *devp;
+
+	if (((devp = of_finddevice("/chosen")) != NULL)
+	    && (of_getprop(devp, "stdout", &of_stdout_handle,
+			   sizeof(of_stdout_handle))
+		== sizeof(of_stdout_handle))) {
+		of_stdout_handle = be32_to_cpu(of_stdout_handle);
+		return 0;
+	}
+
+	return -1;
+}
+
+static void of_console_write(const char *buf, int len)
+{
+	of_call_prom("write", 3, 1, of_stdout_handle, buf, len);
+}
+
+void of_console_init(void)
+{
+	console_ops.open = of_console_open;
+	console_ops.write = of_console_write;
+}