run test only if LLVM version is >= 6.0.0

Author: japaric

src/test/run-make-fulldeps/emit-stack-sizes/Makefile

@@ -6,7 +6,20 @@ all:
 	exit 0
 else
 # check that the .stack_sizes section is generated
+# this test requires LLVM >= 6.0.0
+vers = $(shell llvm-ar -version)
+ifneq (,$(findstring version 3,$(vers)))
+all:
+	exit 0
+else ifneq (,$(findstring version 4,$(vers)))
+all:
+	exit 0
+else ifneq (,$(findstring version 5,$(vers)))
+all:
+	exit 0
+else
 all:
 	$(RUSTC) -C opt-level=3 -Z emit-stack-sizes --emit=obj foo.rs
 	size -A $(TMPDIR)/foo.o | $(CGREP) .stack_sizes
 endif
+endif