diff --git a/tgt-blif/Makefile.in b/tgt-blif/Makefile.in
index 4c9f2d056..8477e5fa6 100644
--- a/tgt-blif/Makefile.in
+++ b/tgt-blif/Makefile.in
@@ -41,7 +41,7 @@ INCLUDE_PATH = -I. -I.. -I$(srcdir) -I$(srcdir)/..
 endif
 
 CPPFLAGS = $(INCLUDE_PATH) @CPPFLAGS@ @DEFS@ @PICFLAG@
-CXXFLAGS = @WARNING_FLAGS@ @CXXFLAGS@
+CXXFLAGS = @WARNING_FLAGS@ @WARNING_FLAGS_CXX@ @CXXFLAGS@
 LDFLAGS = @LDFLAGS@
 
 O = blif.o constants.o logic_gate.o lpm.o lpm_add.o lpm_cmp_eq.o lpm_cmp_gt.o \