[llvm-dev] archiving LTO objects broken for current Xcode releases

[Jack Howarth via llvm-dev]

    The ability to archive object files generated with -flto under
LLVM.org clang 3.9.0 or 4.0svn trunk is broken against the currently
shipping Xcode releases including the upcoming Xcode 8.1 GM.

https://llvm.org/bugs/show_bug.cgi?id=30791

$ clang-3.9 -flto -O1 -c *.i
$ ar cr libtar.a paxerror.o paxexit-status.o paxnames.o rtapelib.o
stdopen.o wordsplit.o xattr-at.o
error: Unknown attribute kind (52) (Producer: 'LLVM3.9.0' Reader:
'LLVM APPLE_1_800.0.42.1_0')
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ar:
internal ranlib command failed

Using MacPorts, I've been able to confirm that archiving LTO object
files now requires a cctools release that has been built against llvm
3.9.0 rather than 3.8.1 to avoid this failure.
     Was this change intentional and is there any possibility of
restoring compatibility with the currently shipping Xcode releases?
          Jack