diff --git a/configure b/configure
index cc3cbd6..e517406 100755
--- a/configure
+++ b/configure
@@ -1861,7 +1861,7 @@
 fi
 if test "$slirp" = "yes" ; then
   echo "CONFIG_SLIRP=y" >> $config_host_mak
-  CFLAGS="-I\$(SRC_PATH)/slirp $CFLAGS"
+  QEMU_CFLAGS="-I\$(SRC_PATH)/slirp $QEMU_CFLAGS"
 fi
 if test "$vde" = "yes" ; then
   echo "CONFIG_VDE=y" >> $config_host_mak