diff --git a/contrib/src/gnutls/rules.mak b/contrib/src/gnutls/rules.mak
index f21a1857cebdd449be295baeefc0d8f4d8ce7b1b..382a97788212dfe778ee74b1e46e3efd6b7580b9 100644
--- a/contrib/src/gnutls/rules.mak
+++ b/contrib/src/gnutls/rules.mak
@@ -59,7 +59,7 @@ endif
 ifdef HAVE_ANDROID
 	cd $< && $(HOSTVARS) gl_cv_header_working_stdint_h=yes ./configure $(GNUTLS_CONF)
 else
-	cd $< && $(HOSTVARS) CFLAGS=$(CFLAGS) ./configure $(GNUTLS_CONF)
+	cd $< && $(HOSTVARS) CFLAGS="$(CFLAGS)" ./configure $(GNUTLS_CONF)
 endif
 	cd $</gl && $(MAKE) install
 	cd $</lib && $(MAKE) install