diff --git a/Makefile b/Makefile
index 624c497..2c5cd7a 100644
--- a/Makefile
+++ b/Makefile
@@ -134,7 +134,7 @@ OPTFLAGS			:= -O2 -ftree-vectorize -flto=$(THREADS)
 LDCXXFLAGS			:= -pthread -D_FORTIFY_SOURCE=2 -D_GLIBCXX_ASSERTIONS $(GOODFLAGS) $(ADDFLAGS)
 override CXXFLAGS	+= $(REQFLAGS) $(LDCXXFLAGS) $(OPTFLAGS) $(WARNFLAGS)
 override LDFLAGS	+= $(LDCXXFLAGS) $(OPTFLAGS) $(WARNFLAGS)
-INC					:= $(foreach incdir,$(INCDIRS),-I$(incdir)) -I$(SRCDIR)
+INC					:= $(foreach incdir,$(INCDIRS),-isystem $(incdir)) -I$(SRCDIR)
 SU_USER				:= root
 
 ifdef DEBUG