-STABLE can no longer build -CURRENT kernel, linker missing ifunc

[Ulrich Spörlein]

Hey all, as of a couple of weeks ago, neither 11.2-RELEASE nor a recent
11-STABLE can buildkernel from head.

This has stopped the Coverity Scan runs dead in its track and I wonder how
anyone would boostrap a move from 11.x to 12.0 then.

% env __MAKE_CONF=/dev/null make buildkernel
make[1]: "/data/freebsd.work/Makefile.inc1" line 343: SYSTEM_COMPILER:
libclang will be built for bootstrapping a cross-compiler.
make[1]: "/data/freebsd.work/Makefile.inc1" line 348: SYSTEM_LINKER:
libclang will be built for bootstrapping a cross-linker.

--------------------------------------------------------------
>>> Kernel build for GENERIC started on Wed Jul 25 14:34:46 CEST 2018
--------------------------------------------------------------
===> GENERIC
mkdir -p /usr/obj/data/freebsd.work/amd64.amd64/sys

--------------------------------------------------------------
>>> stage 1: configuring the kernel
--------------------------------------------------------------
cd /data/freebsd.work/sys/amd64/conf;  PATH=/usr/obj/data/
freebsd.work/amd64.amd64/tmp/legacy/usr/sbin:/usr/obj/data/freebsd.work/amd64.amd64/tmp/legacy/usr/bin:/usr/obj/data/freebsd.work/amd64.amd64/tmp/legacy/bin:/usr/obj/data/freebsd.work/amd64.amd64/tmp/usr/sbin:/usr/obj/data/freebsd.work/amd64.amd64/tmp/usr/bin:/sbin:/bin:/usr/sbin:/usr/bin
config  -d /usr/obj/data/freebsd.work/amd64.amd64/sys/GENERIC  -I '/data/
freebsd.work/sys/amd64/conf' '/data/freebsd.work/sys/amd64/conf/GENERIC'
Kernel build directory is /usr/obj/data/freebsd.work/amd64.amd64/sys/GENERIC
Don't forget to do ``make cleandepend && make depend''

--------------------------------------------------------------
>>> stage 2.1: cleaning up the object tree
--------------------------------------------------------------
cd /usr/obj/data/freebsd.work/amd64.amd64/sys/GENERIC; MACHINE_ARCH=amd64
MACHINE=amd64 CPUTYPE= CC="cc -target x86_64-unknown-freebsd12.0
--sysroot=/usr/obj/data/freebsd.work/amd64.amd64/tmp -B/usr/obj/data/
freebsd.work/amd64.amd64/tmp/usr/bin" CXX="c++  -target
x86_64-unknown-freebsd12.0 --sysroot=/usr/obj/data/
freebsd.work/amd64.amd64/tmp -B/usr/obj/data/
freebsd.work/amd64.amd64/tmp/usr/bin" CPP="cpp -target
x86_64-unknown-freebsd12.0 --sysroot=/usr/obj/data/
freebsd.work/amd64.amd64/tmp -B/usr/obj/data/
freebsd.work/amd64.amd64/tmp/usr/bin" AS="as" AR="ar" LD="ld" LLVM_LINK=""
NM=nm OBJCOPY="objcopy" RANLIB=ranlib STRINGS= SIZE="size" INSTALL="sh
/data/freebsd.work/tools/install.sh" PATH=/usr/obj/data/
freebsd.work/amd64.amd64/tmp/legacy/usr/sbin:/usr/obj/data/freebsd.work/amd64.amd64/tmp/legacy/usr/bin:/usr/obj/data/freebsd.work/amd64.amd64/tmp/legacy/bin:/usr/obj/data/freebsd.work/amd64.amd64/tmp/usr/sbin:/usr/obj/data/freebsd.work/amd64.amd64/tmp/usr/bin:/sbin:/bin:/usr/sbin:/usr/bin
make  -m /data/freebsd.work/share/mk  KERNEL=kernel cleandir
make[2]: "/data/freebsd.work/sys/conf/kern.pre.mk" line 125: amd64 kernel
requires linker ifunc support
*** Error code 1

Stop.
make[1]: stopped in /data/freebsd.work
*** Error code 1

Stop.
make: stopped in /data/freebsd.work