--- a/user/drbdmon/Makefile.in
+++ b/user/drbdmon/Makefile.in
@@ -1,6 +1,6 @@
-CXXFLAGS=-std=c++11 -I. -I../shared -Icppdsaext/src -Wall -Werror -pedantic-errors -fPIC -O2 \
--Wsign-compare -Wpointer-arith -Wswitch-default -Wswitch-enum -Wtype-limits \
--Wmissing-declarations -Wshadow
+CPPFLAGS = -I. -I../shared -Icppdsaext/src
+CXXFLAGS ?= -Wall -Werror -pedantic-errors -fPIC -O2 -Wsign-compare -Wpointer-arith -Wswitch-default -Wswitch-enum -Wtype-limits -Wmissing-declarations -Wshadow
+CXXFLAGS += -std=c++11 -O2 -fPIC
 CXX = @CXX@
 LIBS = @LIBS@
 
@@ -51,7 +51,7 @@ $(dsaext-obj): $(basename $(dsaext-obj)).cpp $(basename $(dsaext-obj)).h
 $(integerparse-obj): $(basename $(integerparse-obj)).cpp $(basename $(integerparse-obj)).h
 
 drbdmon: $(ls-obj)
-	$(CXX) -o $@ $(CPPFLAGS) $(CXXFLAGS) $^ $(LIBS)
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) $(LDFLAGS) $^ $(LIBS) -o $@
 
 # do not try to rebuild Makefile itself
 Makefile: ;