diff --git a/lib/Makefile b/lib/Makefile
index e4ed743..50c38d9 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -21,7 +21,7 @@ OBJS = \
 include ../makeflags
 
 depends.mk: *.cc
-	for x in *.cc; do $(CXX) $(CXXFLAGS) -M "$$x"; done >> depends.mk.new
+	for x in *.cc; do $(CXX) $(CXXFLAGS) -M "$$x"; done > depends.mk.new
 	mv -fv depends.mk.new depends.mk
 
 .version.cc: Makefile ../makeflags *.cc ../include/crucible/*.h
diff --git a/test/Makefile b/test/Makefile
index 7de6261..707b5a8 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -17,7 +17,7 @@ LIBS = -lcrucible
 LDFLAGS = -L../lib -Wl,-rpath=$(shell realpath ../lib)
 
 depends.mk: *.cc
-	for x in *.cc; do $(CXX) $(CXXFLAGS) -M "$$x"; done >> depends.mk.new
+	for x in *.cc; do $(CXX) $(CXXFLAGS) -M "$$x"; done > depends.mk.new
 	mv -fv depends.mk.new depends.mk
 
 -include depends.mk