(off-list for now since it doesn't work correctly when -save-temps or
-via-file-asm are used. I'm not sure how to fix that yet.)
This patch corrects the behaviour of code such as:
.local foo jal foo foo:
to use the correct jal expansion but only when writing ELF files and not when
emitting assembly. The problem lies in the behaviour of MCAsmStreamer vs
MCELFStreamer. MCAsmStreamer emits a '.local foo' directive but doesn't update
the symbol in any way, while MCELFStreamer marks the symbol not-external and
sets the binding to STB_LOCAL.