cmd/link: mark windows/arm as all PIE
If the linker thinks that it's in exe mode instead of pie mode, it
won't emit relocations when generating the pcln table, and we wind
up with crashes like this on windows/arm, where all binaries are
in fact relocated:
Building Go toolchain2 using go_bootstrap and Go toolchain1.
fatal error: minpc or maxpc invalid
runtime: panic before malloc heap initialized
This problem was already solved by darwin/arm64, so solve it the same
way here for windows/arm.
Fixes CL 228478.
Fixes #42786.
Change-Id: I6d1db6907c131183649fc263ccca06783188f344
Reviewed-on: https://go-review.googlesource.com/c/go/+/273566
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Trust: Alex Brainman <alex.brainman@gmail.com>
Trust: Jason A. Donenfeld <Jason@zx2c4.com>