diff --git a/Makefile.in b/Makefile.in
index c7f12e2ca..c1c71075d 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -478,7 +478,7 @@ lua-format:
 
 makefile.dep:
 	$(CXX) -MM $(CPPFLAGS) $(SRCS) > $@
-include makefile.dep
+-include makefile.dep
 
 # These the old names of scripts that have been renamed or deleted. Any
 # scripts with these names will be deleted from the installation
diff --git a/libnetutil/Makefile.in b/libnetutil/Makefile.in
index 017ce2db3..855fa2265 100644
--- a/libnetutil/Makefile.in
+++ b/libnetutil/Makefile.in
@@ -38,4 +38,4 @@ Makefile: Makefile.in
 
 makefile.dep:
 	$(CXX) -MM $(CPPFLAGS) $(SRCS) > $@
-include makefile.dep
+-include makefile.dep
diff --git a/ncat/Makefile.in b/ncat/Makefile.in
index afb00626a..105b29ee9 100644
--- a/ncat/Makefile.in
+++ b/ncat/Makefile.in
@@ -209,5 +209,5 @@ check: $(TARGET) $(TEST_PROGS)
 
 makefile.dep:
 	$(CC) -MM $(CPPFLAGS) $(SRCS) > $@
-include makefile.dep
+-include makefile.dep
 
diff --git a/nmap-update/Makefile.in b/nmap-update/Makefile.in
index 61e00e246..5a5b1495f 100644
--- a/nmap-update/Makefile.in
+++ b/nmap-update/Makefile.in
@@ -59,6 +59,6 @@ Makefile: Makefile.in
 
 makefile.dep:
 	$(CC) -MM $(CPPFLAGS) $(C_FILES) > $@
-include makefile.dep
+-include makefile.dep
 
 .PHONY: all clean
diff --git a/nping/Makefile.in b/nping/Makefile.in
index 5c9a98148..ad5db78be 100644
--- a/nping/Makefile.in
+++ b/nping/Makefile.in
@@ -164,4 +164,4 @@ config.status: configure
 
 makefile.dep:
 	$(CXX) -MM $(CPPFLAGS) $(SRCS) > $@
-include makefile.dep
+-include makefile.dep
diff --git a/nsock/src/Makefile.in b/nsock/src/Makefile.in
index 29497c2d6..cf0b8617b 100644
--- a/nsock/src/Makefile.in
+++ b/nsock/src/Makefile.in
@@ -94,4 +94,4 @@ config.status: configure
 
 makefile.dep:
 	$(CC) -MM $(CPPFLAGS) $(SRCS) > $@
-include makefile.dep
+-include makefile.dep