crt: Simplify msvcrt.dll arm workarounds for __initenv

Remove arch specific ifdefs and instead add dummy symbols to the
arm specific import libs.

Also add a dummy symbol for __winitenv, fixing building apps
that use a wmain() function for arm/aarch64 when targeting msvcrt.dll.

Signed-off-by: Martin Storsjö <martin@martin.st>
4 files changed