diff --git a/fltk-config.in b/fltk-config.in
index 0e4044492..29dde790d 100644
--- a/fltk-config.in
+++ b/fltk-config.in
@@ -289,7 +289,7 @@ if test x$use_images = xyes; then
     LDSTATIC="$libdir/libfltk_images.a $STATICIMAGELIBS $LDSTATIC"
 fi
 
-if test x$use_cairo = xyes -a -n $CAIROLIBS; then
+if test x$use_cairo = xyes -a -n "$CAIROLIBS"; then
     LDLIBS="$CAIROLIBS $LDLIBS"
     LDSTATIC="$CAIROLIBS $LDSTATIC"
 fi