diff --git a/Makefile b/Makefile
index 2188b41..8109cd6 100644
--- a/Makefile
+++ b/Makefile
@@ -51,23 +51,23 @@ install: dist
 
 .PHONY: test
 test: build /tmp/getopt
+	/tmp/getopt
 	tests/posix-compat.sh
 
-/tmp/getopt: src/getopt.rs
-	$(RUSTC) --test -o /tmp/getopt src/getopt.rs
-	/tmp/getopt
+/tmp/getopt: src/libgetopt.rs
+	$(RUSTC) --test -o /tmp/getopt src/libgetopt.rs
 
 .PHONY: rustlibs
 rustlibs: build/o/libsysexits.rlib build/o/libgetopt.rlib \
 	build/o/libstrerror.rlib
 
-build/o/libgetopt.rlib: build src/getopt.rs
+build/o/libgetopt.rlib: build src/libgetopt.rs
 	$(RUSTC) $(RUSTFLAGS) --crate-type=lib --crate-name=getopt \
-		-o $@ src/getopt.rs
+		-o $@ src/libgetopt.rs
 
-build/o/libstrerror.rlib: build src/strerror.rs
+build/o/libstrerror.rlib: build src/libstrerror.rs
 	$(RUSTC) $(RUSTFLAGS) --crate-type=lib -o $@ \
-		src/strerror.rs
+		src/libstrerror.rs
 
 # bandage solution until bindgen(1) gets stdin support
 build/o/libsysexits.rlib: build $(SYSEXITS)sysexits.h
diff --git a/src/getopt.rs b/src/libgetopt.rs
similarity index 100%
rename from src/getopt.rs
rename to src/libgetopt.rs
diff --git a/src/strerror.rs b/src/libstrerror.rs
similarity index 100%
rename from src/strerror.rs
rename to src/libstrerror.rs