WITH_LLVM_TARGET_BPF=yes broken on head

If I do a "make toolchain" with WITH_LLVM_TARGET_BPF=yes set in
/etc/src.conf on the latest head I get the following errors when it
tries to link clang.  I believe that this was broken by the recent'ish
llvm update; it worked as of r351363 back in August.

ld: error: undefined symbol:
llvm::initializeBPFAbstractMemberAccessPass(llvm::PassRegistry&)
>>> referenced by BPFTargetMachine.cpp:37 (/srcpool/src/rstone/freebsd/contrib/llvm/lib/Target/BPF/BPFTargetMachine.cp
p:37)
>>>               BPFTargetMachine.o:(LLVMInitializeBPFTarget) in archive /usr/obj/srcpool/src/rstone/freebsd/amd64.am
d64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::createBPFAbstractMemberAccess()
>>> referenced by BPFTargetMachine.cpp:97 (/srcpool/src/rstone/freebsd/contrib/llvm/lib/Target/BPF/BPFTargetMachine.cp
p:97)
>>>               BPFTargetMachine.o:((anonymous namespace)::BPFPassConfig::addIRPasses()) in archive /usr/obj/srcpool
/src/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::createBPFMISimplifyPatchablePass()
>>> referenced by BPFTargetMachine.cpp:111 (/srcpool/src/rstone/freebsd/contrib/llvm/lib/Target/BPF/BPFTargetMachine.c
pp:111)
>>>               BPFTargetMachine.o:((anonymous namespace)::BPFPassConfig::addMachineSSAOptimization()) in archive /u
sr/obj/srcpool/src/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::BPFCoreSharedInfo::AmaAttr
>>> referenced by string:1427 (/usr/include/c++/v1/string:1427)
>>>               BTFDebug.o:(llvm::BTFDebug::processLDimm64(llvm::MachineInstr const*)) in archive /usr/obj/srcpool/s
rc/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::BPFCoreSharedInfo::AmaAttr
>>> referenced by string:0 (/usr/include/c++/v1/string:0)
>>>               BTFDebug.o:(llvm::BTFDebug::processLDimm64(llvm::MachineInstr const*)) in archive /usr/obj/srcpool/s
rc/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::BPFCoreSharedInfo::AmaAttr
>>> referenced by string:0 (/usr/include/c++/v1/string:0)
>>>               BTFDebug.o:(llvm::BTFDebug::processLDimm64(llvm::MachineInstr const*)) in archive /usr/obj/srcpool/s
rc/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::BPFCoreSharedInfo::AmaAttr
>>> referenced by string:0 (/usr/include/c++/v1/string:0)
>>>               BTFDebug.o:(llvm::BTFDebug::processLDimm64(llvm::MachineInstr const*)) in archive /usr/obj/srcpool/s
rc/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::BPFCoreSharedInfo::PatchableExtSecName
>>> referenced by string:1427 (/usr/include/c++/v1/string:1427)
>>>               BTFDebug.o:(llvm::BTFDebug::processLDimm64(llvm::MachineInstr const*)) in archive /usr/obj/srcpool/s
rc/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::BPFCoreSharedInfo::PatchableExtSecName
>>> referenced by string:0 (/usr/include/c++/v1/string:0)
>>>               BTFDebug.o:(llvm::BTFDebug::processLDimm64(llvm::MachineInstr const*)) in archive /usr/obj/srcpool/s
rc/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::BPFCoreSharedInfo::PatchableExtSecName
>>> referenced by string:0 (/usr/include/c++/v1/string:0)
>>>               BTFDebug.o:(llvm::BTFDebug::processLDimm64(llvm::MachineInstr const*)) in archive /usr/obj/srcpool/s
rc/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::BPFCoreSharedInfo::PatchableExtSecName
>>> referenced by StringRef.h:0 (/srcpool/src/rstone/freebsd/contrib/llvm/include/llvm/ADT/StringRef.h:0)
>>>               BTFDebug.o:(llvm::BTFDebug::processLDimm64(llvm::MachineInstr const*)) in archive /usr/obj/srcpool/s
rc/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::BPFCoreSharedInfo::AmaAttr
>>> referenced by string:1427 (/usr/include/c++/v1/string:1427)
>>>               BTFDebug.o:(llvm::BTFDebug::InstLower(llvm::MachineInstr const*, llvm::MCInst&)) in archive /usr/obj
/srcpool/src/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::BPFCoreSharedInfo::AmaAttr
>>> referenced by string:0 (/usr/include/c++/v1/string:0)
>>>               BTFDebug.o:(llvm::BTFDebug::InstLower(llvm::MachineInstr const*, llvm::MCInst&)) in archive /usr/obj
/srcpool/src/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::BPFCoreSharedInfo::AmaAttr
>>> referenced by string:0 (/usr/include/c++/v1/string:0)
>>>               BTFDebug.o:(llvm::BTFDebug::InstLower(llvm::MachineInstr const*, llvm::MCInst&)) in archive /usr/obj
/srcpool/src/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::BPFCoreSharedInfo::AmaAttr
>>> referenced by string:0 (/usr/include/c++/v1/string:0)
>>>               BTFDebug.o:(llvm::BTFDebug::InstLower(llvm::MachineInstr const*, llvm::MCInst&)) in archive /usr/obj
/srcpool/src/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::BPFCoreSharedInfo::PatchableExtSecName
>>> referenced by string:1427 (/usr/include/c++/v1/string:1427)
>>>               BTFDebug.o:(llvm::BTFDebug::InstLower(llvm::MachineInstr const*, llvm::MCInst&)) in archive /usr/obj
/srcpool/src/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::BPFCoreSharedInfo::PatchableExtSecName
>>> referenced by string:0 (/usr/include/c++/v1/string:0)
>>>               BTFDebug.o:(llvm::BTFDebug::InstLower(llvm::MachineInstr const*, llvm::MCInst&)) in archive /usr/obj
/srcpool/src/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::BPFCoreSharedInfo::PatchableExtSecName
>>> referenced by string:0 (/usr/include/c++/v1/string:0)
>>>               BTFDebug.o:(llvm::BTFDebug::InstLower(llvm::MachineInstr const*, llvm::MCInst&)) in archive /usr/obj
/srcpool/src/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a

ld: error: undefined symbol: llvm::BPFCoreSharedInfo::PatchableExtSecName
>>> referenced by new:0 (/usr/include/c++/v1/new:0)
>>>               BTFDebug.o:(llvm::BTFDebug::InstLower(llvm::MachineInstr const*, llvm::MCInst&)) in archive /usr/obj
/srcpool/src/rstone/freebsd/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/libllvm.a
c++: error: linker command failed with exit code 1 (use -v to see invocation)