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, 38 insertions, 0 deletions

diff --git a/fs/proc/Makefile b/fs/proc/Makefile
new file mode 100644
index 000000000..27e2b26b2
--- /dev/null
+++ b/fs/proc/Makefile
@@ -0,0 +1,38 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the Linux proc filesystem routines.
+#
+
+obj-y   += proc.o
+
+CFLAGS_task_mmu.o	+= -Wno-override-init
+proc-y			:= nommu.o task_nommu.o
+proc-$(CONFIG_MMU)	:= task_mmu.o
+
+proc-y       += inode.o root.o base.o generic.o array.o \
+		fd.o
+proc-$(CONFIG_TTY)      += proc_tty.o
+proc-y	+= cmdline.o
+proc-y	+= consoles.o
+proc-y	+= cpuinfo.o
+proc-y	+= devices.o
+ifneq ($(CONFIG_GENERIC_IRQ_SHOW),y)
+proc-y += interrupts.o
+endif
+proc-y	+= loadavg.o
+proc-y	+= meminfo.o
+proc-y	+= stat.o
+proc-y	+= uptime.o
+proc-y	+= util.o
+proc-y	+= version.o
+proc-y	+= softirqs.o
+proc-y	+= namespaces.o
+proc-y	+= self.o
+proc-y	+= thread_self.o
+proc-$(CONFIG_SYSCTL)		+= proc_sysctl.o
+proc-$(CONFIG_NET)		+= proc_net.o
+proc-$(CONFIG_PROC_KCORE)	+= kcore.o
+proc-$(CONFIG_PROC_VMCORE)	+= vmcore.o
+proc-$(CONFIG_PRINTK)	+= kmsg.o
+proc-$(CONFIG_PROC_PAGE_MONITOR)	+= page.o
+proc-$(CONFIG_BOOT_CONFIG)	+= bootconfig.o