[gn] port c29b29b (_LIBCPP_ASSERTION_SEMANTIC_DEFAULT)

Author: nico

llvm/utils/gn/secondary/libcxx/include/BUILD.gn

@@ -19,6 +19,7 @@ if (current_toolchain == default_toolchain) {
       "_LIBCPP_ABI_FORCE_ITANIUM=",
       "_LIBCPP_ABI_FORCE_MICROSOFT=",
       "_LIBCPP_ABI_VERSION=$libcxx_abi_version",
+      "_LIBCPP_ASSERTION_SEMANTIC_DEFAULT=_LIBCPP_ASSERTION_SEMANTIC_HARDENING_DEPENDENT",
       "_LIBCPP_EXTRA_SITE_DEFINES=",
       "_LIBCPP_HAS_FILESYSTEM=1",
       "_LIBCPP_HAS_THREADS=1",