[openwrt/openwrt] toolchain: Include ./include/fortify for external musl toolchain

[LEDE Commits]

hauke pushed a commit to openwrt/openwrt.git, branch openwrt-22.03:
https://git.openwrt.org/938ae926751672cfac8fe18a1ed6f20ec40b10e5

commit 938ae926751672cfac8fe18a1ed6f20ec40b10e5
Author: Hauke Mehrtens <hauke at hauke-m.de>
AuthorDate: Mon Sep 12 00:31:43 2022 +0200

    toolchain: Include ./include/fortify for external musl toolchain
    
    When building with an external toolcahin with musl also include
    ./include/fortify by default. This is also done when we build with the
    internal toolchain using musl libc.
    
    Without this extra include the fortify source feature is not working
    when using an external musl toolchain. All binaries were compiled
    without fortify source when an external musl toolchain was used. All
    binaries release done by the OpenWrt project use the internal toolcahin
    where fortify source is working.
    
    Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
    (cherry picked from commit b21ddbfa18cd1e437e31dc0fa29408721a186c2a)
---
 toolchain/Config.in | 1 +
 1 file changed, 1 insertion(+)

diff --git a/toolchain/Config.in b/toolchain/Config.in
index 366f5c8b48..f02790ba52 100644
--- a/toolchain/Config.in
+++ b/toolchain/Config.in
@@ -169,6 +169,7 @@ menuconfig EXTERNAL_TOOLCHAIN
 		string
 		prompt "Toolchain include path"  if DEVEL
 		depends on EXTERNAL_TOOLCHAIN && !NATIVE_TOOLCHAIN
+		default "./usr/include ./include/fortify ./include" if EXTERNAL_TOOLCHAIN_LIBC_USE_MUSL
 		default "./usr/include ./include"
 		help
 		  Specify additional directories searched for header files (override