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, 25 insertions, 0 deletions

diff --git a/scripts/prune-kernel b/scripts/prune-kernel
new file mode 100755
index 000000000..dadfd0e47
--- /dev/null
+++ b/scripts/prune-kernel
@@ -0,0 +1,25 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# because I use CONFIG_LOCALVERSION_AUTO, not the same version again and
+# again, /boot and /lib/modules/ eventually fill up.
+# Dumb script to purge that stuff:
+
+for f in "$@"
+do
+        if rpm -qf "/lib/modules/$f" >/dev/null; then
+                echo "keeping $f (installed from rpm)"
+        elif [ $(uname -r) = "$f" ]; then
+                echo "keeping $f (running kernel) "
+        else
+                echo "removing $f"
+                rm -f "/boot/initramfs-$f.img" "/boot/System.map-$f"
+                rm -f "/boot/vmlinuz-$f"   "/boot/config-$f"
+                rm -rf "/lib/modules/$f"
+                if [ -x "$(command -v new-kernel-pkg)" ]; then
+                        new-kernel-pkg --remove $f
+                elif [ -x "$(command -v kernel-install)" ]; then
+                        kernel-install remove $f
+                fi
+        fi
+done