[openwrt/openwrt] gdb: add CPPFLAGS

[LEDE Commits]

hauke pushed a commit to openwrt/openwrt.git, branch openwrt-25.12:
https://git.openwrt.org/361be894b3bf104e782f53105c1d48bfc972a21b

commit 361be894b3bf104e782f53105c1d48bfc972a21b
Author: Hauke Mehrtens <hauke at hauke-m.de>
AuthorDate: Tue Feb 17 01:19:25 2026 +0100

    gdb: add CPPFLAGS
    
    Forward the OpenWrt CPPFLAGS to the compile process. This fixes fortify
    sources support.
    
    Link: https://github.com/openwrt/openwrt/pull/22056
    Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
    (cherry picked from commit 39e5f11631ddce63f46f8ddf338770fe0556990a)
---
 package/devel/gdb/Makefile | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/package/devel/gdb/Makefile b/package/devel/gdb/Makefile
index 6c45de0df9..f935d218ac 100644
--- a/package/devel/gdb/Makefile
+++ b/package/devel/gdb/Makefile
@@ -76,10 +76,12 @@ TARGET_LDFLAGS+= \
 	-static-libstdc++ \
 	-Wl,--gc-sections
 
+MAKE_VARS+= \
+	CPPFLAGS="$(TARGET_CPPFLAGS)"
+
 define Build/Install
 	$(MAKE) -C $(PKG_BUILD_DIR) \
 		DESTDIR="$(PKG_INSTALL_DIR)" \
-		CPPFLAGS="$(TARGET_CPPFLAGS)" \
 		install-gdb install-gdbserver
 endef