This will break some scenario which is to build anything by themself,
which does not use any header or library from the builtin one.
So that's why the spec needs to guard so many conditions, no
-nostartfiles, -nodefaultlibs, -nolibc and -nostdlib appears.
When suitable multilib isn't found, an error is not reported until the
link period, which is inconsistent with the result of compiling option
`-print-multi-directory`. For example, when suitable multilib isn't
found, the return result of `-print-multi-directory` is the default
value '.', while the
