diff --git a/examples/configure_modify_input_source/simple_lib/Makefile.in b/examples/configure_modify_input_source/simple_lib/Makefile.in
index fea277faf..fc566b168 100644
--- a/examples/configure_modify_input_source/simple_lib/Makefile.in
+++ b/examples/configure_modify_input_source/simple_lib/Makefile.in
@@ -1,5 +1,11 @@
+all: simple
+
+.PHONY: all
+
 simple: $(OUTPUT)
 
+.PHONY: simple
+
 $(OUTPUT): ./src/simple.c
 	$(CC) $(CPPFLAGS) -o $(OBJECT) -c ./src/simple.c -I./include -I.
 	$(AR) $(LDFLAGS)
@@ -9,3 +15,5 @@ install: $(OUTPUT)
 	mkdir -p simple/lib
 	cp $(OUTPUT) ./simple/lib/$(OUTPUT)
 	cp -r ./include ./simple
+
+.PHONY: clean test
diff --git a/examples/configure_with_bazel_transitive/simple_lib/Makefile.in b/examples/configure_with_bazel_transitive/simple_lib/Makefile.in
index 223c707a9..225caf9a3 100644
--- a/examples/configure_with_bazel_transitive/simple_lib/Makefile.in
+++ b/examples/configure_with_bazel_transitive/simple_lib/Makefile.in
@@ -1,5 +1,11 @@
+all: simple
+
+.PHONY: all
+
 simple: $(OUTPUT)
 
+.PHONY: simple
+
 $(OUTPUT): ./src/simple.c
 	$(CC) $(CPPFLAGS) -o $(OBJECT) -c ./src/simple.c -I./include -I.
 	$(AR) $(LDFLAGS)
@@ -9,3 +15,5 @@ install:
 	mkdir -p simple/lib
 	cp -p $(OUTPUT) ./simple/lib/$(OUTPUT)
 	cp -rp ./include ./simple
+
+.PHONY: clean test
diff --git a/examples/make_simple/code/Makefile b/examples/make_simple/code/Makefile
index 1dcced175..2b9592bbd 100644
--- a/examples/make_simple/code/Makefile
+++ b/examples/make_simple/code/Makefile
@@ -1,6 +1,6 @@
-BUILD_DIR=build-out
+BUILD_DIR := build-out
 
-UNAME:=$(shell uname)
+UNAME := $(shell uname)
 
 ifneq (,$(findstring NT, $(UNAME)))
   # If Windows
@@ -15,8 +15,12 @@ default all $(BUILD_DIR)/lib/liba.a: liba.cpp liba.h
 	$(CXX_WRAPPER) $(CXXFLAGS) -o $(BUILD_DIR)/lib/liba.o -c liba.cpp
 	ar rcs $(BUILD_DIR)/lib/liba.a $(BUILD_DIR)/lib/liba.o
 
+.PHONY: all
+
 install: $(BUILD_DIR)/lib/liba.a
 	mkdir -p $(PREFIX)/lib $(PREFIX)/include $(PREFIX)/share
 	cp -rpv $(BUILD_DIR)/lib $(PREFIX)
 	cp -p liba.h $(PREFIX)/include
 	cp $(README_DIR)/README.md $(PREFIX)/share/
+
+.PHONY: clean test