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, 60 insertions, 0 deletions

diff --git a/net/ipv6/Makefile b/net/ipv6/Makefile
new file mode 100644
index 000000000..cf5e01f83
--- /dev/null
+++ b/net/ipv6/Makefile
@@ -0,0 +1,60 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the Linux TCP/IP (INET6) layer.
+#
+
+obj-$(CONFIG_IPV6) += ipv6.o
+
+ipv6-y :=	af_inet6.o anycast.o ip6_output.o ip6_input.o addrconf.o \
+		addrlabel.o \
+		route.o ip6_fib.o ipv6_sockglue.o ndisc.o udp.o \
+		raw.o icmp.o mcast.o reassembly.o tcp_ipv6.o ping.o \
+		exthdrs.o datagram.o ip6_flowlabel.o inet6_connection_sock.o \
+		udp_offload.o seg6.o fib6_notifier.o rpl.o ioam6.o
+
+ipv6-$(CONFIG_SYSCTL) += sysctl_net_ipv6.o
+ipv6-$(CONFIG_IPV6_MROUTE) += ip6mr.o
+
+ipv6-$(CONFIG_XFRM) += xfrm6_policy.o xfrm6_state.o xfrm6_input.o \
+	xfrm6_output.o xfrm6_protocol.o
+ipv6-$(CONFIG_NETFILTER) += netfilter.o
+ipv6-$(CONFIG_IPV6_MULTIPLE_TABLES) += fib6_rules.o
+ipv6-$(CONFIG_PROC_FS) += proc.o
+ipv6-$(CONFIG_SYN_COOKIES) += syncookies.o
+ipv6-$(CONFIG_NETLABEL) += calipso.o
+ipv6-$(CONFIG_IPV6_SEG6_LWTUNNEL) += seg6_iptunnel.o seg6_local.o
+ipv6-$(CONFIG_IPV6_SEG6_HMAC) += seg6_hmac.o
+ipv6-$(CONFIG_IPV6_RPL_LWTUNNEL) += rpl_iptunnel.o
+ipv6-$(CONFIG_IPV6_IOAM6_LWTUNNEL) += ioam6_iptunnel.o
+
+obj-$(CONFIG_INET6_AH) += ah6.o
+obj-$(CONFIG_INET6_ESP) += esp6.o
+obj-$(CONFIG_INET6_ESP_OFFLOAD) += esp6_offload.o
+obj-$(CONFIG_INET6_IPCOMP) += ipcomp6.o
+obj-$(CONFIG_INET6_XFRM_TUNNEL) += xfrm6_tunnel.o
+obj-$(CONFIG_INET6_TUNNEL) += tunnel6.o
+obj-$(CONFIG_IPV6_MIP6) += mip6.o
+obj-$(CONFIG_IPV6_ILA) += ila/
+obj-$(CONFIG_NETFILTER)	+= netfilter/
+
+obj-$(CONFIG_IPV6_VTI) += ip6_vti.o
+obj-$(CONFIG_IPV6_SIT) += sit.o
+obj-$(CONFIG_IPV6_TUNNEL) += ip6_tunnel.o
+obj-$(CONFIG_IPV6_GRE) += ip6_gre.o
+obj-$(CONFIG_IPV6_FOU) += fou6.o
+
+obj-y += addrconf_core.o exthdrs_core.o ip6_checksum.o ip6_icmp.o
+obj-$(CONFIG_INET) += output_core.o protocol.o \
+			ip6_offload.o exthdrs_offload.o
+
+obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_hashtables.o
+
+ifneq ($(CONFIG_IPV6),)
+obj-$(CONFIG_NET_UDP_TUNNEL) += ip6_udp_tunnel.o
+obj-y += mcast_snoop.o ndisc_snoop.o
+obj-$(CONFIG_TCP_AO) += tcp_ao.o
+endif
+
+ifdef CONFIG_GCOV_PROFILE_NETFILTER
+GCOV_PROFILE_netfilter.o := y
+endif