diff --git a/Makefile.in b/Makefile.in
index 24cd280386a..fb36b4e1ac6 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -235,6 +235,39 @@ LIBRUST_DSYM_GLOB_$(1) :=$(call CFG_LIB_DSYM_GLOB_$(1),rust)
 
 endef
 
+# $(1) is the path for directory to match against
+# $(2) is the glob to use in the match
+# $(3) is filename (usually the target being created) to filter out from match
+#      (i.e. filename is not out-of-date artifact from prior Rust version/build)
+#
+# Note that a common bug is to accidentally construct the glob denoted
+# by $(2) with a space character prefix, which invalidates the
+# construction $(1)$(2).
+define CHECK_FOR_OLD_GLOB_MATCHES_EXCEPT
+  $(Q)MATCHES="$(filter-out %$(3),$(wildcard $(1)/$(2)))"; if [ -n "$$MATCHES" ] ; then echo "Warning: there are previous" \'$(2)\' "libraries:" $$MATCHES; fi
+endef
+
+# Same interface as above, but deletes rather than just listing the files.
+define REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT
+  $(Q)MATCHES="$(filter-out %$(3),$(wildcard $(1)/$(2)))"; if [ -n "$$MATCHES" ] ; then echo "Warning: removing previous" \'$(2)\' "libraries:" $$MATCHES; rm -v $$MATCHES ; fi
+endef
+
+# We use a different strategy for LIST_ALL_OLD_GLOB_MATCHES_EXCEPT
+# than in the macros above because it needs the result of running the
+# `ls` command after other rules in the command list have run; the
+# macro-expander for $(wildcard ...) would deliver its results too
+# soon. (This is in contrast to the macros above, which are meant to
+# be run at the outset of a command list in a rule.)
+ifdef VERBOSE
+define LIST_ALL_OLD_GLOB_MATCHES_EXCEPT
+  @echo "Info: now are following matches for" '$(2)' "libraries:"
+  @( cd $(1) && ( ls $(2) 2>/dev/null || true ) | grep -v $(3) || true )
+endef
+else
+define LIST_ALL_OLD_GLOB_MATCHES_EXCEPT
+endef
+endif
+
 $(foreach target,$(CFG_TARGET_TRIPLES),\
   $(eval $(call DEF_LIBS,$(target))))
 
diff --git a/mk/host.mk b/mk/host.mk
index ac3bc8ad8cb..ecf84967e5e 100644
--- a/mk/host.mk
+++ b/mk/host.mk
@@ -45,10 +45,12 @@ $$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTC_$(4)): \
 	| $$(HLIB$(2)_H_$(4))/
 
 	@$$(call E, cp: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTC_GLOB_$(4)),$$(notdir $$@))
 	$$(Q)cp $$< $$@
 	$$(Q)cp -R $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBRUSTC_GLOB_$(4)) \
 		$(wildcard $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBRUSTC_DSYM_GLOB_$(4))) \
 	        $$(HLIB$(2)_H_$(4))
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTC_GLOB_$(4)),$$(notdir $$@))
 
 $$(HLIB$(2)_H_$(4))/$(CFG_LIBSYNTAX_$(4)): \
 	$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBSYNTAX_$(4)) \
@@ -58,10 +60,12 @@ $$(HLIB$(2)_H_$(4))/$(CFG_LIBSYNTAX_$(4)): \
 	$$(HEXTRALIB_DEFAULT$(2)_H_$(4)) \
 	| $$(HLIB$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBSYNTAX_GLOB_$(4)),$$(notdir $$@))
 	$$(Q)cp $$< $$@
 	$$(Q)cp -R $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBSYNTAX_GLOB_$(4)) \
 		$$(wildcard $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBSYNTAX_DSYM_GLOB_$(4))) \
 	        $$(HLIB$(2)_H_$(4))
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBSYNTAX_GLOB_$(4)),$$(notdir $$@))
 
 $$(HLIB$(2)_H_$(4))/$(CFG_RUNTIME_$(4)): \
 	$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_RUNTIME_$(4)) \
@@ -74,6 +78,7 @@ $$(HLIB$(2)_H_$(4))/$(CFG_STDLIB_$(4)): \
 	$$(HLIB$(2)_H_$(4))/$(CFG_RUNTIME_$(4)) \
 	| $$(HLIB$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(STDLIB_GLOB_$(4)),$$(notdir $$@))
 	$$(Q)cp $$< $$@
 # Subtle: We do not let the shell expand $(STDLIB_DSYM_GLOB) directly rather
 # we use Make's $$(wildcard) facility. The reason is that, on mac, when using
@@ -85,6 +90,7 @@ $$(HLIB$(2)_H_$(4))/$(CFG_STDLIB_$(4)): \
 	$$(Q)cp -R $$(TLIB$(1)_T_$(4)_H_$(3))/$(STDLIB_GLOB_$(4)) \
 		$$(wildcard $$(TLIB$(1)_T_$(4)_H_$(3))/$(STDLIB_DSYM_GLOB_$(4))) \
 	        $$(HLIB$(2)_H_$(4))
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(STDLIB_GLOB_$(4)),$$(notdir $$@))
 
 $$(HLIB$(2)_H_$(4))/$(CFG_EXTRALIB_$(4)): \
 	$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_EXTRALIB_$(4)) \
@@ -92,10 +98,12 @@ $$(HLIB$(2)_H_$(4))/$(CFG_EXTRALIB_$(4)): \
 	$$(HLIB$(2)_H_$(4))/$(CFG_RUNTIME_$(4)) \
 	| $$(HLIB$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(EXTRALIB_GLOB_$(4)),$$(notdir $$@))
 	$$(Q)cp $$< $$@
 	$$(Q)cp -R $$(TLIB$(1)_T_$(4)_H_$(3))/$(EXTRALIB_GLOB_$(4)) \
 		$$(wildcard $$(TLIB$(1)_T_$(4)_H_$(3))/$(EXTRALIB_DSYM_GLOB_$(4))) \
 	        $$(HLIB$(2)_H_$(4))
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(EXTRALIB_GLOB_$(4)),$$(notdir $$@))
 
 $$(HLIB$(2)_H_$(4))/libstd.rlib: \
 	$$(TLIB$(1)_T_$(4)_H_$(3))/libstd.rlib \
diff --git a/mk/install.mk b/mk/install.mk
index ae6bd29228f..6745535fbca 100644
--- a/mk/install.mk
+++ b/mk/install.mk
@@ -12,17 +12,48 @@
 # For consistency it might be desirable for stageN to be an exact
 # mirror of the installation directory structure.
 
-# Installation macro. Call with source directory as arg 1,
-# destination directory as arg 2, and filename/libname-glob as arg 3
+# Installation macros.
+# For INSTALL,
+# $(1) is the source dirctory
+# $(2) is the destination directory
+# $(3) is the filename/libname-glob
 ifdef VERBOSE
  INSTALL = install -m755 $(1)/$(3) $(2)/$(3)
- INSTALL_LIB = install -m644 `ls -drt1 $(1)/$(3) | tail -1` $(2)/
 else
  INSTALL = $(Q)$(call E, install: $(2)/$(3)) && install -m755 $(1)/$(3) $(2)/$(3)
- INSTALL_LIB = $(Q)$(call E, install_lib: $(2)/$(3)) &&                    \
-	       install -m644 `ls -drt1 $(1)/$(3) | tail -1` $(2)/
 endif
 
+# For INSTALL_LIB,
+# Target-specific $(LIB_SOURCE_DIR) is the source directory
+# Target-specific $(LIB_DESTIN_DIR) is the destination directory
+# $(1) is the filename/libname-glob
+ifdef VERBOSE
+ DO_INSTALL_LIB = install -m644 `ls -drt1 $(LIB_SOURCE_DIR)/$(1) | tail -1` $(LIB_DESTIN_DIR)/
+else
+ DO_INSTALL_LIB = $(Q)$(call E, install_lib: $(LIB_DESTIN_DIR)/$(1)) &&                    \
+	       install -m644 `ls -drt1 $(LIB_SOURCE_DIR)/$(1) | tail -1` $(LIB_DESTIN_DIR)/
+endif
+
+# Target-specific $(LIB_SOURCE_DIR) is the source directory
+# Target-specific $(LIB_DESTIN_DIR) is the destination directory
+# $(1) is the filename/libname-glob
+define INSTALL_LIB
+  $(if $(filter-out 1,$(words $(wildcard $(LIB_SOURCE_DIR)/$(1)))),        \
+       $(error Aborting install because more than one library matching     \
+               $(1) is present in build tree $(LIB_SOURCE_DIR):            \
+               $(wildcard $(LIB_SOURCE_DIR)/$(1))))
+  $(Q)LIB_NAME="$(notdir $(lastword $(wildcard $(LIB_SOURCE_DIR)/$(1))))"; \
+  MATCHES="$(filter-out %$(notdir $(lastword $(wildcard $(LIB_SOURCE_DIR)/$(1)))),\
+                        $(wildcard $(LIB_DESTIN_DIR)/$(1)))";              \
+  if [ -n "$$MATCHES" ]; then                                              \
+    echo "Warning, one or libraries matching Rust library '$(1)'" &&       \
+    echo "  (other than '$$LIB_NAME' itself) already present"     &&       \
+    echo "  at destination $(LIB_DESTIN_DIR):"                    &&       \
+    echo $$MATCHES ;                                                       \
+  fi
+  $(call DO_INSTALL_LIB,$(1))
+endef
+
 # The stage we install from
 ISTAGE = 2
 
@@ -49,38 +80,32 @@ $(foreach target,$(CFG_TARGET_TRIPLES), \
  $(eval $(call INSTALL_PREPARE_N,$(target),$(CFG_BUILD_TRIPLE))))
 
 define INSTALL_TARGET_N
+install-target-$(1)-host-$(2): LIB_SOURCE_DIR=$$(TL$(1)$(2))
+install-target-$(1)-host-$(2): LIB_DESTIN_DIR=$$(PTL$(1)$(2))
 install-target-$(1)-host-$(2): $$(TSREQ$$(ISTAGE)_T_$(1)_H_$(2)) $$(SREQ$$(ISTAGE)_T_$(1)_H_$(2))
 	$$(Q)mkdir -p $$(PTL$(1)$(2))
-	$$(Q)$$(call INSTALL_LIB,$$(TL$(1)$(2)),$$(PTL$(1)$(2)),$$(CFG_RUNTIME_$(1)))
-	$$(Q)$$(call INSTALL_LIB, \
-		$$(TL$(1)$(2)),$$(PTL$(1)$(2)),$$(STDLIB_GLOB_$(1)))
-	$$(Q)$$(call INSTALL_LIB, \
-		$$(TL$(1)$(2)),$$(PTL$(1)$(2)),$$(EXTRALIB_GLOB_$(1)))
-	$$(Q)$$(call INSTALL_LIB,$$(TL$(1)$(2)),$$(PTL$(1)$(2)),libmorestack.a)
+	$$(Q)$$(call INSTALL_LIB,$$(CFG_RUNTIME_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(STDLIB_GLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(EXTRALIB_GLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,libmorestack.a)
 
 endef
 
 define INSTALL_HOST_N
+install-target-$(1)-host-$(2): LIB_SOURCE_DIR=$$(TL$(1)$(2))
+install-target-$(1)-host-$(2): LIB_DESTIN_DIR=$$(PTL$(1)$(2))
 install-target-$(1)-host-$(2): $$(CSREQ$$(ISTAGE)_T_$(1)_H_$(2))
 	$$(Q)mkdir -p $$(PTL$(1)$(2))
-	$$(Q)$$(call INSTALL_LIB,$$(TL$(1)$(2)),$$(PTL$(1)$(2)),$$(CFG_RUNTIME_$(1)))
-	$$(Q)$$(call INSTALL_LIB, \
-		$$(TL$(1)$(2)),$$(PTL$(1)$(2)),$$(STDLIB_GLOB_$(1)))
-	$$(Q)$$(call INSTALL_LIB, \
-		$$(TL$(1)$(2)),$$(PTL$(1)$(2)),$$(EXTRALIB_GLOB_$(1)))
-	$$(Q)$$(call INSTALL_LIB, \
-		$$(TL$(1)$(2)),$$(PTL$(1)$(2)),$$(LIBRUSTC_GLOB_$(1)))
-	$$(Q)$$(call INSTALL_LIB, \
-		$$(TL$(1)$(2)),$$(PTL$(1)$(2)),$$(LIBSYNTAX_GLOB_$(1)))
-	$$(Q)$$(call INSTALL_LIB, \
-		$$(TL$(1)$(2)),$$(PTL$(1)$(2)),$$(LIBRUSTPKG_GLOB_$(1)))
-	$$(Q)$$(call INSTALL_LIB, \
-		$$(TL$(1)$(2)),$$(PTL$(1)$(2)),$$(LIBRUSTDOC_GLOB_$(1)))
-	$$(Q)$$(call INSTALL_LIB, \
-		$$(TL$(1)$(2)),$$(PTL$(1)$(2)),$$(LIBRUSTI_GLOB_$(1)))
-	$$(Q)$$(call INSTALL_LIB, \
-		$$(TL$(1)$(2)),$$(PTL$(1)$(2)),$$(LIBRUST_GLOB_$(1)))
-	$$(Q)$$(call INSTALL_LIB,$$(TL$(1)$(2)),$$(PTL$(1)$(2)),libmorestack.a)
+	$$(Q)$$(call INSTALL_LIB,$$(CFG_RUNTIME_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(STDLIB_GLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(EXTRALIB_GLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(LIBRUSTC_GLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(LIBSYNTAX_GLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(LIBRUSTPKG_GLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(LIBRUSTDOC_GLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(LIBRUSTI_GLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(LIBRUST_GLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,libmorestack.a)
 
 endef
 
@@ -104,6 +129,8 @@ PHB = $(PREFIX_BIN)
 # Shorthand for the prefix bin directory
 PHL = $(PREFIX_LIB)
 
+install-host: LIB_SOURCE_DIR=$(HL)
+install-host: LIB_DESTIN_DIR=$(PHL)
 install-host: $(CSREQ$(ISTAGE)_T_$(CFG_BUILD_TRIPLE)_H_$(CFG_BUILD_TRIPLE))
 	$(Q)mkdir -p $(PREFIX_BIN)
 	$(Q)mkdir -p $(PREFIX_LIB)
@@ -113,14 +140,14 @@ install-host: $(CSREQ$(ISTAGE)_T_$(CFG_BUILD_TRIPLE)_H_$(CFG_BUILD_TRIPLE))
 	$(Q)$(call INSTALL,$(HB2),$(PHB),rustdoc$(X_$(CFG_BUILD_TRIPLE)))
 	$(Q)$(call INSTALL,$(HB2),$(PHB),rusti$(X_$(CFG_BUILD_TRIPLE)))
 	$(Q)$(call INSTALL,$(HB2),$(PHB),rust$(X_$(CFG_BUILD_TRIPLE)))
-	$(Q)$(call INSTALL_LIB,$(HL),$(PHL),$(STDLIB_GLOB_$(CFG_BUILD_TRIPLE)))
-	$(Q)$(call INSTALL_LIB,$(HL),$(PHL),$(EXTRALIB_GLOB_$(CFG_BUILD_TRIPLE)))
-	$(Q)$(call INSTALL_LIB,$(HL),$(PHL),$(LIBRUSTC_GLOB_$(CFG_BUILD_TRIPLE)))
-	$(Q)$(call INSTALL_LIB,$(HL),$(PHL),$(LIBSYNTAX_GLOB_$(CFG_BUILD_TRIPLE)))
-	$(Q)$(call INSTALL_LIB,$(HL),$(PHL),$(LIBRUSTI_GLOB_$(CFG_BUILD_TRIPLE)))
-	$(Q)$(call INSTALL_LIB,$(HL),$(PHL),$(LIBRUST_GLOB_$(CFG_BUILD_TRIPLE)))
-	$(Q)$(call INSTALL_LIB,$(HL),$(PHL),$(LIBRUSTPKG_GLOB_$(CFG_BUILD_TRIPLE)))
-	$(Q)$(call INSTALL_LIB,$(HL),$(PHL),$(LIBRUSTDOC_GLOB_$(CFG_BUILD_TRIPLE)))
+	$(Q)$(call INSTALL_LIB,$(STDLIB_GLOB_$(CFG_BUILD_TRIPLE)))
+	$(Q)$(call INSTALL_LIB,$(EXTRALIB_GLOB_$(CFG_BUILD_TRIPLE)))
+	$(Q)$(call INSTALL_LIB,$(LIBRUSTC_GLOB_$(CFG_BUILD_TRIPLE)))
+	$(Q)$(call INSTALL_LIB,$(LIBSYNTAX_GLOB_$(CFG_BUILD_TRIPLE)))
+	$(Q)$(call INSTALL_LIB,$(LIBRUSTI_GLOB_$(CFG_BUILD_TRIPLE)))
+	$(Q)$(call INSTALL_LIB,$(LIBRUST_GLOB_$(CFG_BUILD_TRIPLE)))
+	$(Q)$(call INSTALL_LIB,$(LIBRUSTPKG_GLOB_$(CFG_BUILD_TRIPLE)))
+	$(Q)$(call INSTALL_LIB,$(LIBRUSTDOC_GLOB_$(CFG_BUILD_TRIPLE)))
 	$(Q)$(call INSTALL,$(HL),$(PHL),$(CFG_RUNTIME_$(CFG_BUILD_TRIPLE)))
 	$(Q)$(call INSTALL,$(HL),$(PHL),$(CFG_RUSTLLVM_$(CFG_BUILD_TRIPLE)))
 	$(Q)$(call INSTALL,$(S)/man, \
diff --git a/mk/stage0.mk b/mk/stage0.mk
index a1aaef4d554..7d0255db4ac 100644
--- a/mk/stage0.mk
+++ b/mk/stage0.mk
@@ -1,10 +1,16 @@
 # Extract the snapshot host compiler
 
+$(HBIN0_H_$(CFG_BUILD_TRIPLE))/:
+	mkdir -p $@
 
+$(HLIB0_H_$(CFG_BUILD_TRIPLE))/:
+	mkdir -p $@
 
 $(HBIN0_H_$(CFG_BUILD_TRIPLE))/rustc$(X_$(CFG_BUILD_TRIPLE)):		\
 		$(S)src/snapshots.txt					\
-		$(S)src/etc/get-snapshot.py $(MKFILE_DEPS)
+		$(S)src/etc/get-snapshot.py $(MKFILE_DEPS)		\
+		| $(HBIN0_H_$(CFG_BUILD_TRIPLE))/
+
 	@$(call E, fetch: $@)
 #   Note: the variable "SNAPSHOT_FILE" is generally not set, and so
 #   we generally only pass one argument to this script.
@@ -22,23 +28,28 @@ endif
 # Host libs will be extracted by the above rule
 
 $(HLIB0_H_$(CFG_BUILD_TRIPLE))/$(CFG_RUNTIME_$(CFG_BUILD_TRIPLE)): \
-		$(HBIN0_H_$(CFG_BUILD_TRIPLE))/rustc$(X_$(CFG_BUILD_TRIPLE))
+		$(HBIN0_H_$(CFG_BUILD_TRIPLE))/rustc$(X_$(CFG_BUILD_TRIPLE)) \
+		| $(HLIB0_H_$(CFG_BUILD_TRIPLE))/
 	$(Q)touch $@
 
 $(HLIB0_H_$(CFG_BUILD_TRIPLE))/$(CFG_STDLIB_$(CFG_BUILD_TRIPLE)): \
-		$(HBIN0_H_$(CFG_BUILD_TRIPLE))/rustc$(X_$(CFG_BUILD_TRIPLE))
+		$(HBIN0_H_$(CFG_BUILD_TRIPLE))/rustc$(X_$(CFG_BUILD_TRIPLE)) \
+		| $(HLIB0_H_$(CFG_BUILD_TRIPLE))/
 	$(Q)touch $@
 
 $(HLIB0_H_$(CFG_BUILD_TRIPLE))/$(CFG_EXTRALIB_$(CFG_BUILD_TRIPLE)): \
-		$(HBIN0_H_$(CFG_BUILD_TRIPLE))/rustc$(X_$(CFG_BUILD_TRIPLE))
+		$(HBIN0_H_$(CFG_BUILD_TRIPLE))/rustc$(X_$(CFG_BUILD_TRIPLE)) \
+		| $(HLIB0_H_$(CFG_BUILD_TRIPLE))/
 	$(Q)touch $@
 
 $(HLIB0_H_$(CFG_BUILD_TRIPLE))/$(CFG_LIBRUSTC_$(CFG_BUILD_TRIPLE)): \
-		$(HBIN0_H_$(CFG_BUILD_TRIPLE))/rustc$(X_$(CFG_BUILD_TRIPLE))
+		$(HBIN0_H_$(CFG_BUILD_TRIPLE))/rustc$(X_$(CFG_BUILD_TRIPLE)) \
+		| $(HLIB0_H_$(CFG_BUILD_TRIPLE))/
 	$(Q)touch $@
 
 $(HLIB0_H_$(CFG_BUILD_TRIPLE))/$(CFG_RUSTLLVM_$(CFG_BUILD_TRIPLE)): \
-		$(HBIN0_H_$(CFG_BUILD_TRIPLE))/rustc$(X_$(CFG_BUILD_TRIPLE))
+		$(HBIN0_H_$(CFG_BUILD_TRIPLE))/rustc$(X_$(CFG_BUILD_TRIPLE)) \
+		| $(HLIB0_H_$(CFG_BUILD_TRIPLE))/
 	$(Q)touch $@
 
 # For other targets, let the host build the target:
@@ -48,33 +59,51 @@ define BOOTSTRAP_STAGE0
   # $(2) stage to bootstrap from
   # $(3) target to bootstrap from
 
-$$(HBIN0_H_$(1))/rustc$$(X_$(1)):								\
-		$$(TBIN$(2)_T_$(1)_H_$(3))/rustc$$(X_$(1))
+$(HBIN0_H_$(1))/:
+	mkdir -p $@
+
+$(HLIB0_H_$(1))/:
+	mkdir -p $@
+
+$$(HBIN0_H_$(1))/rustc$$(X_$(1)): \
+		$$(TBIN$(2)_T_$(1)_H_$(3))/rustc$$(X_$(1)) \
+		| $(HBIN0_H_$(1))/
 	@$$(call E, cp: $$@)
 	$$(Q)cp $$< $$@
 
 $$(HLIB0_H_$(1))/$(CFG_RUNTIME_$(1)): \
-		$$(TLIB$(2)_T_$(1)_H_$(3))/$(CFG_RUNTIME_$(1))
+		$$(TLIB$(2)_T_$(1)_H_$(3))/$(CFG_RUNTIME_$(1)) \
+		| $(HLIB0_H_$(1))/
 	@$$(call E, cp: $$@)
 	$$(Q)cp $$< $$@
 
 $$(HLIB0_H_$(1))/$(CFG_STDLIB_$(1)): \
-		$$(TLIB$(2)_T_$(1)_H_$(3))/$(CFG_STDLIB_$(1))
+		$$(TLIB$(2)_T_$(1)_H_$(3))/$(CFG_STDLIB_$(1)) \
+		| $(HLIB0_H_$(1))/
 	@$$(call E, cp: $$@)
+	$$(call CHECK_FOR_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(EXTRALIB_GLOB_$(4)),$$(notdir $$@))
 	$$(Q)cp $$(TLIB$(2)_T_$(1)_H_$(3))/$(STDLIB_GLOB_$(1)) $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(EXTRALIB_GLOB_$(4)),$$(notdir $$@))
 
 $$(HLIB0_H_$(1))/$(CFG_EXTRALIB_$(1)): \
-		$$(TLIB$(2)_T_$(1)_H_$(3))/$(CFG_EXTRALIB_$(1))
+		$$(TLIB$(2)_T_$(1)_H_$(3))/$(CFG_EXTRALIB_$(1)) \
+		| $(HLIB0_H_$(1))/
 	@$$(call E, cp: $$@)
+	$$(call CHECK_FOR_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(EXTRALIB_GLOB_$(4)),$$(notdir $$@))
 	$$(Q)cp $$(TLIB$(2)_T_$(1)_H_$(3))/$(EXTRALIB_GLOB_$(1)) $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(EXTRALIB_GLOB_$(4)),$$(notdir $$@))
 
 $$(HLIB0_H_$(1))/$(CFG_LIBRUSTC_$(1)): \
-		$$(TLIB$(2)_T_$(1)_H_$(3))/$(CFG_LIBRUSTC_$(1))
+		$$(TLIB$(2)_T_$(1)_H_$(3))/$(CFG_LIBRUSTC_$(1)) \
+		| $(HLIB0_H_$(1))/
 	@$$(call E, cp: $$@)
+	$$(call CHECK_FOR_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTC_GLOB_$(4)),$$(notdir $$@))
 	$$(Q)cp $$(TLIB$(2)_T_$(1)_H_$(3))/$(LIBRUSTC_GLOB_$(1)) $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTC_GLOB_$(4)),$$(notdir $$@))
 
 $$(HLIB0_H_$(1))/$(CFG_RUSTLLVM_$(1)): \
-		$$(TLIB$(2)_T_$(1)_H_$(3))/$(CFG_RUSTLLVM_$(1))
+		$$(TLIB$(2)_T_$(1)_H_$(3))/$(CFG_RUSTLLVM_$(1)) \
+		| $(HLIB0_H_$(1))/
 	@$$(call E, cp: $$@)
 	$$(Q)cp $$< $$@
 
diff --git a/mk/target.mk b/mk/target.mk
index 47ab7c86728..e3d4b985449 100644
--- a/mk/target.mk
+++ b/mk/target.mk
@@ -48,7 +48,9 @@ $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_STDLIB_$(2)): \
 		$$(TSREQ$(1)_T_$(2)_H_$(3)) \
 		| $$(TLIB$(1)_T_$(2)_H_$(3))/
 	@$$(call E, compile_and_link: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(STDLIB_GLOB_$(2)),$$(notdir $$@))
 	$$(STAGE$(1)_T_$(2)_H_$(3)) $$(WFLAGS_ST$(1)) -o $$@ $$< && touch $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(STDLIB_GLOB_$(2)),$$(notdir $$@))
 
 $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_EXTRALIB_$(2)): \
 		$$(EXTRALIB_CRATE) $$(EXTRALIB_INPUTS) \
@@ -56,7 +58,9 @@ $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_EXTRALIB_$(2)): \
 		$$(TSREQ$(1)_T_$(2)_H_$(3)) \
 		| $$(TLIB$(1)_T_$(2)_H_$(3))/
 	@$$(call E, compile_and_link: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(EXTRALIB_GLOB_$(2)),$$(notdir $$@))
 	$$(STAGE$(1)_T_$(2)_H_$(3)) $$(WFLAGS_ST$(1)) -o $$@ $$< && touch $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(EXTRALIB_GLOB_$(2)),$$(notdir $$@))
 
 $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBSYNTAX_$(3)): \
                 $$(LIBSYNTAX_CRATE) $$(LIBSYNTAX_INPUTS) \
@@ -65,7 +69,9 @@ $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBSYNTAX_$(3)): \
 		$$(TEXTRALIB_DEFAULT$(1)_T_$(2)_H_$(3)) \
 		| $$(TLIB$(1)_T_$(2)_H_$(3))/
 	@$$(call E, compile_and_link: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBSYNTAX_GLOB_$(2)),$$(notdir $$@))
 	$$(STAGE$(1)_T_$(2)_H_$(3)) $(BORROWCK) -o $$@ $$< && touch $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBSYNTAX_GLOB_$(2)),$$(notdir $$@))
 
 # Only build the compiler for host triples
 ifneq ($$(findstring $(2),$$(CFG_HOST_TRIPLES)),)
@@ -83,7 +89,9 @@ $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBRUSTC_$(3)):		\
                 $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_RUSTLLVM_$(3)) \
 		| $$(TLIB$(1)_T_$(2)_H_$(3))/
 	@$$(call E, compile_and_link: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTC_GLOB_$(2)),$$(notdir $$@))
 	$$(STAGE$(1)_T_$(2)_H_$(3)) -o $$@ $$< && touch $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTC_GLOB_$(2)),$$(notdir $$@))
 
 $$(TBIN$(1)_T_$(2)_H_$(3))/rustc$$(X_$(3)):			\
 		$$(DRIVER_CRATE)				\
diff --git a/mk/tools.mk b/mk/tools.mk
index 0e83147501c..5afabbcb336 100644
--- a/mk/tools.mk
+++ b/mk/tools.mk
@@ -39,7 +39,8 @@ $$(TBIN$(1)_T_$(4)_H_$(3))/compiletest$$(X_$(4)):			\
 		$$(COMPILETEST_CRATE) $$(COMPILETEST_INPUTS)	\
 		$$(TSREQ$(1)_T_$(4)_H_$(3))						\
 		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_STDLIB_$(4))      \
-		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_EXTRALIB_$(4))
+		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_EXTRALIB_$(4))    \
+		| $$(TBIN$(1)_T_$(4)_H_$(3))/
 	@$$(call E, compile_and_link: $$@)
 	$$(STAGE$(1)_T_$(4)_H_$(3)) -o $$@ $$<
 
@@ -48,13 +49,17 @@ $$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTPKG_$(4)):		\
 		$$(TSREQ$(1)_T_$(4)_H_$(3))					\
 		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_STDLIB_$(4))	\
 		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_EXTRALIB_$(4))	\
-		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTC_$(4))
+		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTC_$(4)) \
+		| $$(TLIB$(1)_T_$(4)_H_$(3))/
 	@$$(call E, compile_and_link: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTPKG_GLOB_$(4)),$$(notdir $$@))
 	$$(STAGE$(1)_T_$(4)_H_$(3)) $$(WFLAGS_ST$(1)) -o $$@ $$< && touch $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTPKG_GLOB_$(4)),$$(notdir $$@))
 
 $$(TBIN$(1)_T_$(4)_H_$(3))/rustpkg$$(X_$(4)):				\
 		$$(DRIVER_CRATE) 							\
-		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTPKG_$(4))
+		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTPKG_$(4)) \
+		| $$(TBIN$(1)_T_$(4)_H_$(3))/
 	@$$(call E, compile_and_link: $$@)
 	$$(STAGE$(1)_T_$(4)_H_$(3)) --cfg rustpkg -o $$@ $$<
 
@@ -63,13 +68,17 @@ $$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTDOC_$(4)):		\
 		$$(TSREQ$(1)_T_$(4)_H_$(3))					\
 		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_STDLIB_$(4))	\
 		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_EXTRALIB_$(4))	\
-		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTC_$(4))
+		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTC_$(4)) \
+		| $$(TLIB$(1)_T_$(4)_H_$(3))/
 	@$$(call E, compile_and_link: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTDOC_GLOB_$(4)),$$(notdir $$@))
 	$$(STAGE$(1)_T_$(4)_H_$(3)) -o $$@ $$< && touch $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTDOC_GLOB_$(4)),$$(notdir $$@))
 
 $$(TBIN$(1)_T_$(4)_H_$(3))/rustdoc$$(X_$(4)):			\
 		$$(DRIVER_CRATE) 							\
-		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTDOC_$(4))
+		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTDOC_$(4))			\
+		| $$(TBIN$(1)_T_$(4)_H_$(3))/
 	@$$(call E, compile_and_link: $$@)
 	$$(STAGE$(1)_T_$(4)_H_$(3)) --cfg rustdoc -o $$@ $$<
 
@@ -78,13 +87,17 @@ $$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTI_$(4)):		\
 		$$(TSREQ$(1)_T_$(4)_H_$(3))					\
 		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_STDLIB_$(4))	\
 		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_EXTRALIB_$(4))	\
-		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTC_$(4))
+		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTC_$(4))	\
+		| $$(TLIB$(1)_T_$(4)_H_$(3))/
 	@$$(call E, compile_and_link: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTI_GLOB_$(4)),$$(notdir $$@))
 	$$(STAGE$(1)_T_$(4)_H_$(3)) -o $$@ $$< && touch $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTI_GLOB_$(4)),$$(notdir $$@))
 
 $$(TBIN$(1)_T_$(4)_H_$(3))/rusti$$(X_$(4)):			\
 		$$(DRIVER_CRATE) 							\
-		$$(TLIB$(1)_T_$(4)_H_$(4))/$(CFG_LIBRUSTI_$(4))
+		$$(TLIB$(1)_T_$(4)_H_$(4))/$(CFG_LIBRUSTI_$(4)) \
+		| $$(TBIN$(1)_T_$(4)_H_$(3))/
 	@$$(call E, compile_and_link: $$@)
 	$$(STAGE$(1)_T_$(4)_H_$(3)) --cfg rusti -o $$@ $$<
 
@@ -96,13 +109,17 @@ $$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUST_$(4)):		\
 		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTPKG_$(4))	\
 		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTI_$(4))		\
 		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTDOC_$(4))	\
-		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTC_$(4))
+		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTC_$(4))		\
+		| $$(TLIB$(1)_T_$(4)_H_$(3))/
 	@$$(call E, compile_and_link: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUST_GLOB_$(4)),$$(notdir $$@))
 	$$(STAGE$(1)_T_$(4)_H_$(3)) -o $$@ $$< && touch $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUST_GLOB_$(4)),$$(notdir $$@))
 
 $$(TBIN$(1)_T_$(4)_H_$(3))/rust$$(X_$(4)):			\
 		$$(DRIVER_CRATE) 							\
-		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUST_$(4))
+		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUST_$(4)) \
+		| $$(TBIN$(1)_T_$(4)_H_$(3))/
 	@$$(call E, compile_and_link: $$@)
 	$$(STAGE$(1)_T_$(4)_H_$(3)) --cfg rust -o $$@ $$<
 
@@ -112,7 +129,8 @@ define TOOLS_STAGE_N_HOST
 
 $$(HBIN$(2)_H_$(4))/compiletest$$(X_$(4)):				\
 		$$(TBIN$(1)_T_$(4)_H_$(3))/compiletest$$(X_$(4))	\
-		$$(HSREQ$(2)_H_$(4))
+		$$(HSREQ$(2)_H_$(4))					\
+		| $$(HBIN$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
 	$$(Q)cp $$< $$@
 
@@ -120,9 +138,12 @@ $$(HBIN$(2)_H_$(4))/compiletest$$(X_$(4)):				\
 $$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTPKG_$(4)):				\
 		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTPKG_$(4))	\
 		$$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTC_$(4))		\
-		$$(HSREQ$(2)_H_$(4))
+		$$(HSREQ$(2)_H_$(4))					\
+		| $$(HLIB$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTPKG_GLOB_$(4)),$$(notdir $$@))
 	$$(Q)cp $$< $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTPKG_GLOB_$(4)),$$(notdir $$@))
 	$$(Q)cp -R $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBRUSTPKG_GLOB_$(4)) \
 		$$(wildcard $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBRUSTPKG_DSYM_GLOB_$(4))) \
 	        $$(HLIB$(2)_H_$(4))
@@ -130,16 +151,20 @@ $$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTPKG_$(4)):				\
 $$(HBIN$(2)_H_$(4))/rustpkg$$(X_$(4)):				\
 		$$(TBIN$(1)_T_$(4)_H_$(3))/rustpkg$$(X_$(4))	\
 		$$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTPKG_$(4))	\
-		$$(HSREQ$(2)_H_$(4))
+		$$(HSREQ$(2)_H_$(4))				\
+		| $$(HBIN$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
 	$$(Q)cp $$< $$@
 
 $$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTDOC_$(4)):					\
 		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTDOC_$(4))	\
 		$$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTC_$(4))			\
-		$$(HSREQ$(2)_H_$(4))
+		$$(HSREQ$(2)_H_$(4)) \
+		| $$(HLIB$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTDOC_GLOB_$(4)),$$(notdir $$@))
 	$$(Q)cp $$< $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTDOC_GLOB_$(4)),$$(notdir $$@))
 	$$(Q)cp -R $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBRUSTDOC_GLOB_$(4)) \
 		$$(wildcard $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBRUSTDOC_DSYM_GLOB_$(4))) \
 	        $$(HLIB$(2)_H_$(4))
@@ -147,16 +172,20 @@ $$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTDOC_$(4)):					\
 $$(HBIN$(2)_H_$(4))/rustdoc$$(X_$(4)):				\
 		$$(TBIN$(1)_T_$(4)_H_$(3))/rustdoc$$(X_$(4))	\
 		$$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTDOC_$(4))	\
-		$$(HSREQ$(2)_H_$(4))
+		$$(HSREQ$(2)_H_$(4))				\
+		| $$(HBIN$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
 	$$(Q)cp $$< $$@
 
 $$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTI_$(4)):					\
 		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTI_$(4))	\
 		$$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTC_$(4))			\
-		$$(HSREQ$(2)_H_$(4))
+		$$(HSREQ$(2)_H_$(4)) \
+		| $$(HLIB$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTI_GLOB_$(4)),$$(notdir $$@))
 	$$(Q)cp $$< $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTI_GLOB_$(4)),$$(notdir $$@))
 	$$(Q)cp -R $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBRUSTI_GLOB_$(4)) \
 		$$(wildcard $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBRUSTI_DSYM_GLOB_$(4))) \
 	        $$(HLIB$(2)_H_$(4))
@@ -164,16 +193,20 @@ $$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTI_$(4)):					\
 $$(HBIN$(2)_H_$(4))/rusti$$(X_$(4)):				\
 		$$(TBIN$(1)_T_$(4)_H_$(3))/rusti$$(X_$(4))	\
 		$$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTI_$(4))	\
-		$$(HSREQ$(2)_H_$(4))
+		$$(HSREQ$(2)_H_$(4))				\
+		| $$(HBIN$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
 	$$(Q)cp $$< $$@
 
 $$(HLIB$(2)_H_$(4))/$(CFG_LIBRUST_$(4)):					\
 		$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUST_$(4))	\
-		$$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTC_$(4))			\
-		$$(HSREQ$(2)_H_$(4))
+		$$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTC_$(4))	\
+		$$(HSREQ$(2)_H_$(4))				\
+		| $$(HLIB$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUST_GLOB_$(4)),$$(notdir $$@))
 	$$(Q)cp $$< $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUST_GLOB_$(4)),$$(notdir $$@))
 	$$(Q)cp -R $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBRUST_GLOB_$(4)) \
 		$$(wildcard $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBRUST_DSYM_GLOB)_$(4)) \
 	        $$(HLIB$(2)_H_$(4))
@@ -181,7 +214,8 @@ $$(HLIB$(2)_H_$(4))/$(CFG_LIBRUST_$(4)):					\
 $$(HBIN$(2)_H_$(4))/rust$$(X_$(4)):				\
 		$$(TBIN$(1)_T_$(4)_H_$(3))/rust$$(X_$(4))	\
 		$$(HLIB$(2)_H_$(4))/$(CFG_LIBRUST_$(4))	\
-		$$(HSREQ$(2)_H_$(4))
+		$$(HSREQ$(2)_H_$(4))				\
+		| $$(HBIN$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
 	$$(Q)cp $$< $$@
 
diff --git a/src/etc/get-snapshot.py b/src/etc/get-snapshot.py
index 130ace64ce4..af1a6d6da7b 100755
--- a/src/etc/get-snapshot.py
+++ b/src/etc/get-snapshot.py
@@ -8,9 +8,20 @@ def unpack_snapshot(triple, dl_path):
   print("opening snapshot " + dl_path)
   tar = tarfile.open(dl_path)
   kernel = get_kernel(triple)
+
+  stagep = os.path.join(triple, "stage0")
+
+  # Remove files from prior unpackings, since snapshot rustc may not
+  # be able to disambiguate between multiple candidate libraries.
+  # (Leave dirs in place since extracting step still needs them.)
+  for root, _, files in os.walk(stagep):
+    for f in files:
+      print("removing " + os.path.join(root, f))
+      os.unlink(os.path.join(root, f))
+
   for p in tar.getnames():
     name = p.replace("rust-stage0/", "", 1);
-    stagep = os.path.join(triple, "stage0")
+
     fp = os.path.join(stagep, name)
     print("extracting " + p)
     tar.extract(p, download_unpack_base)