diff --git a/libxrdp/Makefile.am b/libxrdp/Makefile.am
index bd044d77..0452c1da 100644
--- a/libxrdp/Makefile.am
+++ b/libxrdp/Makefile.am
@@ -23,6 +23,10 @@ AM_CPPFLAGS += -DXRDP_NEUTRINORDP
 LIBXRDP_EXTRA_LIBS += $(FREERDP_LIBS)
 endif
 
+if XRDP_RFXCODEC
+AM_CPPFLAGS += -DXRDP_RFXCODEC
+endif
+
 if XRDP_TJPEG
 AM_CPPFLAGS += -DXRDP_JPEG -DXRDP_TJPEG @TurboJpegIncDir@
 AM_LDFLAGS += @TurboJpegLibDir@