auto merge of #6728 : alexcrichton/rust/update-linenoise, r=Aatch

This updates the bundled linenoise library, and explicitly builds it with UTF8 support. This way rusti correctly handles utf8 characters when doing line operations.

Closes #6681

Author: bors

mk/platform.mk

@@ -29,7 +29,7 @@ $(foreach t,$(CFG_TARGET_TRIPLES),$(info cfg: os for $(t) is $(OSTYPE_$(t))))
 # FIXME: no-omit-frame-pointer is just so that task_start_wrapper
 # has a frame pointer and the stack walker can understand it. Turning off
 # frame pointers everywhere is overkill
-CFG_GCCISH_CFLAGS += -fno-omit-frame-pointer
+CFG_GCCISH_CFLAGS += -fno-omit-frame-pointer -DUSE_UTF8
 
 # On Darwin, we need to run dsymutil so the debugging information ends
 # up in the right place.  On other platforms, it automatically gets