[openwrt/openwrt] u-boot.mk: add support for config customization

[LEDE Commits]

ynezz pushed a commit to openwrt/openwrt.git, branch openwrt-23.05:
https://git.openwrt.org/c05c0699d4798b02f8ee88159236142e08c0c4cd

commit c05c0699d4798b02f8ee88159236142e08c0c4cd
Author: Petr Štetiar <ynezz at true.cz>
AuthorDate: Fri Jun 2 13:54:20 2023 +0200

    u-boot.mk: add support for config customization
    
    Make it possible to easily customize U-Boot config options via new
    `UBOOT_CUSTOMIZE_CONFIG` variable, so we don't need to patch config
    files or override config step with shell hackery.
    
    This generic approach uses `config` CLI to tweak the .config as needed,
    for example:
    
     UBOOT_CUSTOMIZE_CONFIG := \
            --enable CMD_EFIDEBUG \
            --enable CMD_BOOTMENU \
            --enable AUTOBOOT \
            --enable AUTOBOOT_MENU_SHOW \
            --disable AUTOBOOT_KEYED \
            --disable AUTOBOOT_USE_MENUKEY \
            --disable BOOTMENU_DISABLE_UBOOT_CONSOLE \
            --set-val BOOTDELAY 2
    
    Signed-off-by: Petr Štetiar <ynezz at true.cz>
    (cherry picked from commit 186b97590b9b2f47abc535c9df0687e00e60f78e)
---
 include/u-boot.mk | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/u-boot.mk b/include/u-boot.mk
index 8945e8e2b8..2b8106410f 100644
--- a/include/u-boot.mk
+++ b/include/u-boot.mk
@@ -83,6 +83,9 @@ endef
 
 define Build/Configure/U-Boot
 	+$(MAKE) $(PKG_JOBS) -C $(PKG_BUILD_DIR) $(UBOOT_CONFIGURE_VARS) $(UBOOT_CONFIG)_config
+	$(if $(strip $(UBOOT_CUSTOMIZE_CONFIG)),
+		$(PKG_BUILD_DIR)/scripts/config --file $(PKG_BUILD_DIR)/.config $(UBOOT_CUSTOMIZE_CONFIG)
+		+$(MAKE) $(PKG_JOBS) -C $(PKG_BUILD_DIR) $(UBOOT_CONFIGURE_VARS) oldconfig)
 endef
 
 DTC=$(wildcard $(LINUX_DIR)/scripts/dtc/dtc)