--- a/examples/kegogi/Makefile
+++ b/examples/kegogi/Makefile
@@ -1,4 +1,4 @@
-CFLAGS=-g -I../../src -Isrc -Wall -Wextra
+CFLAGS+=-I../../src -Isrc -Wall -Wextra
 LIBS=-lzmq -lsqlite3
 
 all: kegogi
@@ -8,10 +8,10 @@ install: all
 
 kegogi: src/kegogi.o src/fuzzrnd.o src/kegogi_parser.o src/httpclient.o src/param.o src/kegogi_lexer.o src/kegogi_tokens.o
 	mkdir -p build
-	$(CC) ${CFLAGS} -o build/kegogi src/kegogi.o src/kegogi_parser.o src/kegogi_lexer.o src/fuzzrnd.o src/httpclient.o src/param.o src/kegogi_tokens.o ${LIBS} ../../build/libm2.a
+	$(CC) $(CPPFLAGS) ${CFLAGS} $(LDFLAGS) -o build/kegogi src/kegogi.o src/kegogi_parser.o src/kegogi_lexer.o src/fuzzrnd.o src/httpclient.o src/param.o src/kegogi_tokens.o ${LIBS} ../../build/libm2.a
 
 src/kegogi_lexer.o: src/kegogi_lexer.c
-	$(CC) $(CFLAGS) -c src/kegogi_lexer.c -o src/kegogi_lexer.o
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -c src/kegogi_lexer.c -o src/kegogi_lexer.o
 
 src/kegogi_lexer.c: src/kegogi_lexer.rl src/kegogi_parser.h
 	ragel src/kegogi_lexer.rl -C -o src/kegogi_lexer.c
--- a/tests/filters/Makefile
+++ b/tests/filters/Makefile
@@ -1,12 +1,12 @@
 PREFIX?=/usr/local
-CFLAGS=-I../../src -I../../src/mbedtls/include $(OPTFLAGS) -fPIC -shared -nostartfiles -L../../build
-LDFLAGS=$(OPTLIBS)
+CFLAGS+=-I../../src -I../../src/mbedtls/include -fPIC -shared -nostartfiles -L../../build
+LDFLAGS+=$(OPTLIBS)
 
 all: test_filter.so test_filter_a.so test_filter_b.so test_filter_c.so
 
 
 %.so : %.c ../../build/libm2.a
-	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $< ../../build/libm2.a
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ $< ../../build/libm2.a
 
 clean:
 	rm -f *.so
--- a/tools/config_modules/Makefile
+++ b/tools/config_modules/Makefile
@@ -1,6 +1,6 @@
 PREFIX?=/usr/local
-CFLAGS=-I../../src -I../../src/mbedtls/include $(OPTFLAGS) -fPIC -shared -nostartfiles -L../../build
-LDFLAGS=$(OPTLIBS)
+CFLAGS+=-I../../src -I../../src/mbedtls/include -fPIC -shared -nostartfiles -L../../build
+LDFLAGS+=$(OPTLIBS)
 
 MONGO_SRC = mongo-c-driver/src/bson.c \
             mongo-c-driver/src/encoding.c \
@@ -22,11 +22,11 @@ fetch_mongo_c_driver:
 mongodb.so: CFLAGS += $(MONGO_CFLAGS)
 mongodb.so: fetch_mongo_c_driver
 mongodb.so: mongodb.c
-	$(CC) $(CFLAGS) -c $(MONGO_SRC)
-	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $< bson.o encoding.o gridfs.o md5.o mongo.o env_posix.o numbers.o ../../build/libm2.a
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -c $(MONGO_SRC)
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ $< bson.o encoding.o gridfs.o md5.o mongo.o env_posix.o numbers.o ../../build/libm2.a
 
 %.so : %.c
-	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $< ../../build/libm2.a
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ $< ../../build/libm2.a
 
 clean:
 	rm -f *.o *.so
--- a/tools/filters/Makefile
+++ b/tools/filters/Makefile
@@ -1,12 +1,12 @@
 PREFIX?=/usr/local
-CFLAGS=-I../../src -I../../src/mbedtls/include $(OPTFLAGS) -g -fPIC -shared -nostartfiles -L../../build
-LDFLAGS=$(OPTLIBS)
+CFLAGS+=-I../../src -I../../src/mbedtls/include -fPIC -shared -nostartfiles -L../../build
+LDFLAGS+=$(OPTLIBS)
 
 all: null.so rewrite.so sendfile.so
 
 
 %.so : %.c
-	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $< ../../build/libm2.a
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ $< ../../build/libm2.a
 
 clean:
 	rm -f *.so
--- a/tools/m2sh/Makefile
+++ b/tools/m2sh/Makefile
@@ -1,4 +1,4 @@
-CFLAGS=-DNDEBUG -DNO_LINENOS -pthread -g -I../../src -Isrc -Wall $(OPTFLAGS)
+CFLAGS+=-DNDEBUG -DNO_LINENOS -pthread -g -I../../src -Isrc -Wall
 LIBS=-lzmq -lsqlite3 ../../build/libm2.a $(OPTLIBS)
 
 PREFIX?=/usr/local
@@ -11,7 +11,7 @@ LIB_OBJ=$(filter-out src/m2sh.o,${OBJECTS})
 
 all: ../lemon/lemon tests build/m2sh
 
-dev: CFLAGS=-g -Wall -Wextra -Isrc -I../../src $(OPTFLAGS)
+dev: CFLAGS+=-Wall -Wextra -Isrc -I../../src $(OPTFLAGS)
 dev: all
 
 install: build/m2sh
@@ -19,15 +19,15 @@ install: build/m2sh
 
 build/libm2sh.a: ${LIB_OBJ}
 	mkdir -p build
-	ar rcs $@ ${LIB_OBJ}
-	ranlib $@
+	$(AR) rcs $@ ${LIB_OBJ}
+	$(RANLIB) $@
 
 build/m2sh: ../lemon/lemon ../../build/libm2.a ${OBJECTS}
 	mkdir -p build
-	$(CC) $(CFLAGS) -o build/m2sh ${OBJECTS} ../../build/libm2.a $(LIBS)
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -o build/m2sh ${OBJECTS} ../../build/libm2.a $(LIBS)
 
 ../lemon/lemon: ../lemon/lemon.c
-	$(CC) -O2 ../lemon/lemon.c -o ../lemon/lemon
+	$(CC) $(CPPFLAGS) $(LDFLAGS) ../lemon/lemon.c -o ../lemon/lemon
 
 tests: build/libm2sh.a ${TESTS}
 	sh ./tests/runtests.sh
@@ -39,7 +39,7 @@ tests: build/libm2sh.a ${TESTS}
 	ragel -G2 $<
 
 $(TESTS): %: %.c build/libm2sh.a
-	$(CC) $(CFLAGS) -o $@ $< build/libm2sh.a ../../build/libm2.a $(LIBS)
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ $< build/libm2sh.a ../../build/libm2.a $(LIBS)
 
 ../../build/libm2.a:
 	cd ../.. && make clean all
--- a/tools/procer/Makefile
+++ b/tools/procer/Makefile
@@ -1,4 +1,4 @@
-CFLAGS=-DNDEBUG -pthread -g -I../../src -Wall $(OPTFLAGS)
+CFLAGS+=-DNDEBUG -pthread -g -I../../src -Wall
 PREFIX?=/usr/local
 LIBS?=-lzmq 
 SOURCES=$(wildcard *.c)
@@ -8,7 +8,7 @@ all: procer
 
 
 procer: ../../build/libm2.a ${OBJECTS}
-	$(CC) $(OPTFLAGS) $(OPTLIBS) -o $@ ${OBJECTS} ../../build/libm2.a ${LIBS}
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ ${OBJECTS} ../../build/libm2.a ${LIBS}
 
 clean:
 	rm -f *.o procer