[pragma] Enable error -Wdelete-non-virtual-dtor
Currently fails directwrite backend.
diff --git a/src/hb.hh b/src/hb.hh
index 0b1be17..c59986e 100644
--- a/src/hb.hh
+++ b/src/hb.hh
@@ -52,6 +52,7 @@
/* Error. Should never happen. */
#pragma GCC diagnostic error "-Wc++11-narrowing"
#pragma GCC diagnostic error "-Wcast-align"
+#pragma GCC diagnostic error "-Wdelete-non-virtual-dtor"
#pragma GCC diagnostic error "-Wformat-security"
#pragma GCC diagnostic error "-Wimplicit-function-declaration"
#pragma GCC diagnostic error "-Winit-self"
