Make qemu-palcode build environment standalone. NFC.

Don't include system headers.  Instead, provide standalone definitions
and declarations of types needed and functions used by the PALcode that
are compatible with the standard Alpha / GCC ABI.

Signed-off-by: Jason Thorpe <thorpej@me.com>
Message-Id: <20210603035317.6814-2-thorpej@me.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
5 files changed