libunwind: Fix build with musl+security flags

Fixes
src/os-linux.c:63: undefined reference to `__stack_chk_fail_local'

(From OE-Core rev: 43894faa45884dcc3b6111ed67e1a96fbec019a8)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-support/libunwind/libunwind_1.2.1.bb

@@ -21,3 +21,5 @@ ARM_INSTRUCTION_SET_armv4 = "arm"
 ARM_INSTRUCTION_SET_armv5 = "arm"
 
 LDFLAGS += "-Wl,-z,relro,-z,now ${@bb.utils.contains('DISTRO_FEATURES', 'ld-is-gold', ' -fuse-ld=bfd ', '', d)}"
+
+SECURITY_LDFLAGS_append_libc-musl = " -lssp_nonshared"