diff --git a/sys/unix/Makefile.src b/sys/unix/Makefile.src
index 3c47316fc..415b404c2 100644
--- a/sys/unix/Makefile.src
+++ b/sys/unix/Makefile.src
@@ -176,7 +176,7 @@ SYSOBJ = $(TARGETPFX)ioctl.o $(TARGETPFX)unixmain.o $(TARGETPFX)unixtty.o \
 # The Qt and Be window systems are written in C++, while the rest of
 # NetHack is standard C.  If using Qt, uncomment the LINK line here to get
 # the C++ libraries linked in.
-CXXFLAGS = -I. -I$(QTDIR)/include $(QTCXXFLAGS)
+CXXFLAGS = $(CFLAGS) -I. -I$(QTDIR)/include $(QTCXXFLAGS)
 CXX ?= g++
 MOC ?= moc
 #LINK=g++