diff --git a/devel/flex/Makefile b/devel/flex/Makefile
index 5f2c12e0..3b7d1ce1 100644
--- a/devel/flex/Makefile
+++ b/devel/flex/Makefile
@@ -36,6 +36,12 @@ endef
 
 CONFIGURE_ARGS += --disable-shared --disable-bootstrap
 
+define Build/InstallDev
+	$(INSTALL_DIR) $(1)/usr/include $(1)/usr/lib
+	$(CP) $(PKG_INSTALL_DIR)/usr/include/* $(1)/usr/include/
+	$(CP) $(PKG_INSTALL_DIR)/usr/lib/* $(1)/usr/lib/
+endef
+
 define Package/flex/install
 	$(INSTALL_DIR) $(1)/usr/bin/
 	$(CP) \