Fix an sh error

Didn't think it was this particular about things, but I also should
have tested locally.

It makes sense, though---`\` followed by LF would eat it, so we'd have
`sysroot done` instead of `sysroot; done` as it is parsed.  This should
pass now.

Signed-off-by: Kristofer Rye <kristofer.rye@gmail.com>
Tested-by: Kristofer Rye <kristofer.rye@gmail.com>

src/test/run-make-fulldeps/print-target-list/Makefile

@@ -4,5 +4,5 @@
 # target specifications
 all:
 	for target in $(shell $(BARE_RUSTC) --print target-list); do \
-		$(BARE_RUSTC) --target $$target --print sysroot \
+		$(BARE_RUSTC) --target $$target --print sysroot; \
 	done