diff --git a/vtysh/extract.pl.in b/vtysh/extract.pl.in
index 0b9ee51..6f1ee93 100755
--- a/vtysh/extract.pl.in
+++ b/vtysh/extract.pl.in
@@ -62,7 +62,7 @@
 foreach (@ARGV) {
     $file = $_;
 
-    open (FH, "cpp -DHAVE_CONFIG_H -DVTYSH_EXTRACT_PL -DHAVE_IPV6 -I@top_builddir@ -I@srcdir@/ -I@srcdir@/.. -I@top_srcdir@/lib -I@top_srcdir@/isisd/topology @SNMP_INCLUDES@ $file |");
+    open (FH, "cpp -DHAVE_CONFIG_H -DVTYSH_EXTRACT_PL -DHAVE_IPV6 -I@top_builddir@ -I@srcdir@/ -I@srcdir@/.. -I@top_srcdir@/lib -I@top_srcdir@/isisd/topology @SNMP_INCLUDES@ @CPPFLAGS@ $file |");
     local $/; undef $/;
     $line = <FH>;
     close (FH);