diff --git a/src/Makefile b/src/Makefile
index 16c3e97..efff2bd 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1,7 +1,9 @@
 
-CXX = g++
-CXXFLAGS = -O3
-AR = ar
+DESTDIR ?= /usr/local
+CXX ?= g++
+CXXFLAGS ?= -O3
+AR ?= ar
+PROTOC ?= protoc
 
 all: libosmpbf.a ../include/osmpbf/fileformat.pb.h ../include/osmpbf/osmformat.pb.h
 
@@ -12,16 +14,16 @@ libosmpbf.a: fileformat.pb.o osmformat.pb.o
 	$(CXX) $(CXXFLAGS) -c -o $@ $<
 
 %.pb.cc ../include/osmpbf/%.pb.h: %.proto
-	protoc --proto_path=. --cpp_out=. $<
+	$(PROTOC) --proto_path=. --cpp_out=. $<
 	cp *.pb.h ../include/osmpbf/
 
 install:
-	install -m 755 -g root -o root -d $(DESTDIR)/usr/lib
-	install -m 644 -g root -o root libosmpbf.a $(DESTDIR)/usr/lib
-	install -m 755 -g root -o root -d $(DESTDIR)/usr/include/osmpbf
-	install -m 644 -g root -o root ../include/osmpbf/osmpbf.h $(DESTDIR)/usr/include/osmpbf
-	install -m 644 -g root -o root ../include/osmpbf/fileformat.pb.h $(DESTDIR)/usr/include/osmpbf
-	install -m 644 -g root -o root ../include/osmpbf/osmformat.pb.h $(DESTDIR)/usr/include/osmpbf
+	install -m 755 -d $(DESTDIR)/usr/lib
+	install -m 644 libosmpbf.a $(DESTDIR)/usr/lib
+	install -m 755 -d $(DESTDIR)/usr/include/osmpbf
+	install -m 644 ../include/osmpbf/osmpbf.h $(DESTDIR)/usr/include/osmpbf
+	install -m 644 ../include/osmpbf/fileformat.pb.h $(DESTDIR)/usr/include/osmpbf
+	install -m 644 ../include/osmpbf/osmformat.pb.h $(DESTDIR)/usr/include/osmpbf
 
 clean:
 	rm -f *.pb.h *.pb.cc *.pb.o libosmpbf.a
diff --git a/tools/Makefile b/tools/Makefile
index b9fc26b..f175577 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -1,7 +1,8 @@
 
-CXX = g++
-CXXFLAGS = -g -I../include
-LDFLAGS = -L../src -lpthread -lz -lprotobuf-lite -losmpbf
+DESTDIR ?= /usr/local
+CXX ?= g++
+CXXFLAGS ?= -g -I../include
+LDFLAGS ?= -L../src -lpthread -lz -lprotobuf-lite -losmpbf
 
 all: osmpbf-outline
 
@@ -9,8 +10,8 @@ osmpbf-outline: osmpbf-outline.cpp
 	$(CXX) $(CXXFLAGS) -o $@ $< $(LDFLAGS)
 
 install:
-	install -m 755 -g root -o root -d $(DESTDIR)/usr/bin
-	install -m 644 -g root -o root -s osmpbf-outline $(DESTDIR)/usr/bin
+	install -m 755 -d $(DESTDIR)/usr/bin
+	install -m 644 -s osmpbf-outline $(DESTDIR)/usr/bin
 
 clean:
 	rm -f osmpbf-outline