SVN r273381/2 breaks world

>From an empty obj tree on the second pass through, I get ..

--- tblgen ---
c++ -O2 -pipe
-I/usr/src/usr.bin/clang/tblgen/../../../contrib/llvm/include
-I/usr/src/usr.bin/clang/tblgen/../../../contrib/llvm/tools/clang/include -I/usr/src/usr.bin/clang/tblgen/../../../contrib/llvm/utils/TableGen
-I.
-I/usr/src/usr.bin/clang/tblgen/../../../contrib/llvm/../../lib/clang/include
-DLLVM_ON_UNIX -DLLVM_ON_FREEBSD -D__STDC_LIMIT_MACROS
-D__STDC_CONSTANT_MACROS -fno-strict-aliasing
-DLLVM_DEFAULT_TARGET_TRIPLE=\"x86_64-unknown-freebsd11.0\"
-DLLVM_HOST_TRIPLE=\"x86_64-unknown-freebsd11.0\" -DDEFAULT_SYSROOT=\"\"
-Qunused-arguments -I/usr/obj/usr/src/tmp/legacy/usr/include
-fno-exceptions -fno-rtti -Wno-c++11-extensions  -static
-L/usr/obj/usr/src/tmp/legacy/usr/lib -o tblgen AsmMatcherEmitter.o
AsmWriterEmitter.o AsmWriterInst.o CTagsEmitter.o CallingConvEmitter.o
CodeEmitterGen.o CodeGenDAGPatterns.o CodeGenInstruction.o
CodeGenMapTable.o CodeGenRegisters.o CodeGenSchedule.o CodeGenTarget.o
DAGISelEmitter.o DAGISelMatcher.o DAGISelMatcherEmitter.o
DAGISelMatcherGen.o DAGISelMatcherOpt.o DFAPacketizerEmitter.o
DisassemblerEmitter.o FastISelEmitter.o FixedLenDecoderEmitter.o
InstrInfoEmitter.o IntrinsicEmitter.o OptParserEmitter.o
PseudoLoweringEmitter.o RegisterInfoEmitter.o SetTheory.o
SubtargetEmitter.o TGValueTypes.o TableGen.o X86DisassemblerTables.o
X86ModRMFilters.o X86RecognizableInstr.o
/usr/obj/usr/src/tmp/usr/src/usr.bin/clang/tblgen/../../../lib/clang/libllvmtablegen/libllvmtablegen.a
/usr/obj/usr/src/tmp/usr/src/usr.bin/clang/tblgen/../../../lib/clang/libllvmsupport/libllvmsupport.a
-lncursesw -legacy
/usr/lib/libc++.a(cxxrt_stdexcept.o):(.rodata+0x1c0): multiple
definition of `typeinfo for std::bad_array_new_length'
/usr/lib/libc++.a(new.o):(.rodata+0x90): first defined here
/usr/lib/libc++.a(cxxrt_stdexcept.o):(.rodata+0x1a0): multiple
definition of `typeinfo name for std::bad_array_new_length'
/usr/lib/libc++.a(new.o):(.rodata+0x70): first defined here
/usr/lib/libc++.a(cxxrt_stdexcept.o):(.rodata+0xc0): multiple definition
of `vtable for std::bad_array_new_length'
/usr/lib/libc++.a(new.o):(.rodata+0x10): first defined here
c++: error: linker command failed with exit code 1 (use -v to see
invocation)
*** [tblgen] Error code 1

make[3]: stopped in /usr/src/usr.bin/clang/tblgen
1 error

Recompiling and reinstalling libc++ doesn't change anything,

	imb