rename aux to auxiliary, since aux is apparently reserved on windows

Author: nikomatsakis

mk/tests.mk

@@ -253,7 +253,7 @@ CTEST_COMMON_ARGS$(1)-T-$(2)-H-$(3) :=						\
 		--compile-lib-path $$(HLIB$(1)_H_$(3))				\
         --run-lib-path $$(TLIB$(1)_T_$(2)_H_$(3))			\
         --rustc-path $$(HBIN$(1)_H_$(3))/rustc$$(X)			\
-        --aux-base $$(S)src/test/aux/                       \
+        --aux-base $$(S)src/test/auxiliary/                 \
         --stage-id stage$(1)-$(2)							\
         --rustcflags "$$(CFG_RUSTC_FLAGS) --target=$(2) --inline"	\
         $$(CTEST_TESTARGS)