diff --git a/Makefile.in b/Makefile.in
index 7137aab..5062d5e 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -3,6 +3,7 @@ VPATH=%VPATH%
 RUSTC ?= rustc
 RUSTDOC ?= rustdoc
 RUSTFLAGS ?= -O
+HOST_RUSTFLAGS ?= -O
 
 PHF_SRC := $(VPATH)/src/phf.rs
 PHF_MAC_SRC := $(VPATH)/src/phf_mac.rs
@@ -10,14 +11,22 @@ PHF_TEST_SRC := $(VPATH)/src/test.rs
 
 all:
 	$(MAKE) phf.dummy
+	$(MAKE) phf_host.dummy
 	$(MAKE) phf_mac.dummy
 
 phf.dummy: $(PHF_SRC)
 	$(RUSTC) $(RUSTFLAGS) $< --out-dir .
 	touch $@
 
+# phf_mac depends on phf, so it must be built once for
+# the target platform, and again for the host platform.
+phf_host.dummy: $(PHF_SRC)
+	mkdir -p host
+	$(RUSTC) $(HOST_RUSTFLAGS) $< --out-dir host
+	touch $@
+
 phf_mac.dummy: $(PHF_MAC_SRC)
-	$(RUSTC) $(RUSTFLAGS) -L . $< --out-dir .
+	$(RUSTC) $(HOST_RUSTFLAGS) -L host $< --out-dir .
 	touch $@
 
 check: phf_test.dummy
@@ -26,6 +35,7 @@ phf_test.dummy: $(PHF_TEST_SRC)
 	$(RUSTC) --test $(RUSTFLAGS) -L . $< --out-dir .
 
 clean:
+	rm -rf host
 	rm -f *.o *.a *.so *.dylib *.rlib *.dll *.dummy *.exe *-test
 
 .PHONY: all check clean
diff --git a/src/test.rs b/src/test.rs
index 89d6d1d..446e7de 100644
--- a/src/test.rs
+++ b/src/test.rs
@@ -3,10 +3,9 @@
 #[phase(syntax)]
 extern crate phf_mac;
 extern crate phf;
-extern crate collections;
 
 mod map {
-    use collections::{HashMap, HashSet};
+    use std::collections::{HashMap, HashSet};
     use phf::PhfMap;
 
     #[allow(dead_code)]
@@ -119,7 +118,7 @@ mod map {
 }
 
 mod set {
-    use collections::HashSet;
+    use std::collections::HashSet;
     use phf::PhfSet;
 
     #[allow(dead_code)]