Comment 4 for bug 1349789

BTW I think some history may be at work here. clang didn't support native cpu detection back when I was the chief clang person at BlackBerry, it may well still not. I would assume the default choice of arm-linux-gnueabihf, judging from google searching, was mainly driven by RaspPI enthusiasts who obviously wanted an ARMv6 clang. Now, a Cortex-A8 supports atomics just fine, but it could be that arm-linux-gnueabihf means one thing to GCC (an ARMv6) and something rather less (an ARM7tdmi for example, the lowest supported ARM CPU) to clang which is ARMv4 or something.

It might be worth experimenting with a default triple for clang of armv6-linux-gnueabihf instead. After all, Ubuntu surely does not work on systems without atomics. I'll give this a try on Saturday and see what happens.

BTW there is something real weird in Boost on clang armhf, exception throw catches aren't reliable, this was causing an infinite loop of terminate(). I'd say 1.56 is going to ship anyway, I'll see if I can figure out the problem for 1.57, again this will be Saturday.

Niall