sandbox: Fix LTO to work with STACKPROTECTOR

Add the STACKPROTECTOR symbols to the script that generates the
symbols that should not be removed by the use of LTO when linking
a shared object. This prevents a fail to build due to link errors.

https://source.denx.de/u-boot/u-boot/-/issues/35

Signed-off-by: Andrew Goodbody <andrew.goodbody@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>

scripts/gen_ll_addressable_symbols.sh

@@ -11,5 +11,6 @@
 set -e
 
 echo '#include <linux/compiler.h>'
-$@ 2>/dev/null | grep -oe '_u_boot_list_2_[a-zA-Z0-9_]*_2_[a-zA-Z0-9_]*' | \
-	sort -u | sed -e 's/^\(.*\)/extern char \1[];\n__ADDRESSABLE(\1);/'
+$@ 2>/dev/null | grep -oe '_u_boot_list_2_[a-zA-Z0-9_]*_2_[a-zA-Z0-9_]*' \
+	-e '__stack_chk_guard' | sort -u | \
+	sed -e 's/^\(.*\)/extern char \1[];\n__ADDRESSABLE(\1);/'