[jchw]

What's weird is that the Clang binary is clearly compiled for an instruction set that is compatible with the Pi B+, but it doesn't target an instruction set that is compatible with the Pi B+. This is genuinely weird, since that's not meant to be a cross-compiler; in theory, the host and the target should be the same.

Presumably the image is Raspbian. I don't see a reason why not to assume that.

[guipsp]

One key thing is missing from your comment (which explains the 'weirdness') - clang, and other llvm-family tools are cross-compatible by default. There is no separate cross compilation binary. This is just a configuration bug.

[jchw]

Yes, that's true, although it doesn't actually explain the weirdness. I compile Clang all the time and there's no obvious reason why you'd get cross-compiled binaries out of Clang if you just compile and install it normally. The bug, configuration or otherwise, is the weirdness.