Revert r140589. It was causing failures during llvm compilation:

llvm[1]: Compiling CommandLine.cpp for Debug+Asserts build
if  /Users/void/llvm/llvm-opt.obj/Release+Asserts/bin/clang++ -I/Users/void/llvm/llvm.obj/include -I/Users/void/llvm/llvm.obj/lib/Support -I/Users/void/llvm/llvm.src/include -I/Users/void/llvm/llvm.src/lib/Support  -D_DEBUG -D_GNU_SOURCE -D__STDC_LIMIT_MACROS -D__STDC_CONSTANT_MACROS -g -fno-exceptions -fno-common -Woverloaded-virtual -Wcast-qual   -m64 -Wall -W -Wno-unused-parameter -Wwrite-strings -c -MMD -MP -MF "/Users/void/llvm/llvm.obj/lib/Support/Debug+Asserts/CommandLine.d.tmp" -MT "/Users/void/llvm/llvm.obj/lib/Support/Debug+Asserts/CommandLine.o" -MT "/Users/void/llvm/llvm.obj/lib/Support/Debug+Asserts/CommandLine.d" /Users/void/llvm/llvm.src/lib/Support/CommandLine.cpp -o /Users/void/llvm/llvm.obj/lib/Support/Debug+Asserts/CommandLine.o ; \
            then /bin/mv -f "/Users/void/llvm/llvm.obj/lib/Support/Debug+Asserts/CommandLine.d.tmp" "/Users/void/llvm/llvm.obj/lib/Support/Debug+Asserts/CommandLine.d"; else /bin/rm "/Users/void/llvm/llvm.obj/lib/Support/Debug+Asserts/CommandLine.d.tmp"; exit 1; fi
In file included from /Users/void/llvm/llvm.src/lib/Support/CommandLine.cpp:25:
/Users/void/llvm/llvm.src/include/llvm/Support/system_error.h:690:14: error: unknown type name 'make_error_condition'; did you mean 'error_condition'?
    {*this = make_error_condition(_e);}
             ^~~~~~~~~~~~~~~~~~~~
             error_condition
...

llvm-svn: 140599