Make rav1e cli error more verbose if wasm target for benchmarking

[vibhoothi]

We can try to make the CLI bit more verbose when it is wasm target along with windows error.

Reference:
Originally posted by @lu-zero in #2451 (comment)

[englishm]

Hi!

It looks like this issue pertains to this code:

rav1e/src/bin/rav1e.rs

Lines 409 to 433 in 6ca4bc7

	cfg_if::cfg_if! {
	if #[cfg(any(target_os = "windows", target_arch = "wasm32"))] {
	fn print_rusage() {
	eprintln!("Windows benchmarking is not supported currently.");
	}
	} else {
	fn print_rusage() {
	// SAFETY: This uses an FFI, it is safe because we call it correctly.
	let (utime, stime, maxrss) = unsafe {
	let mut usage = std::mem::zeroed();
	let _ = libc::getrusage(libc::RUSAGE_SELF, &mut usage);
	(usage.ru_utime, usage.ru_stime, usage.ru_maxrss)
	};
	eprintln!(
	"user time: {} s",
	utime.tv_sec as f64 + utime.tv_usec as f64 / 1_000_000f64
	);
	eprintln!(
	"system time: {} s",
	stime.tv_sec as f64 + stime.tv_usec as f64 / 1_000_000f64
	);
	eprintln!("maximum rss: {maxrss} KB");
	}
	}
	}

and this code:

rav1e/src/bin/rav1e-ch.rs

Lines 420 to 444 in 6ca4bc7

	cfg_if::cfg_if! {
	if #[cfg(any(target_os = "windows", target_arch = "wasm32"))] {
	fn print_rusage() {
	eprintln!("Windows benchmarking is not supported currently.");
	}
	} else {
	fn print_rusage() {
	// SAFETY: This uses an FFI, it is safe because we call it correctly.
	let (utime, stime, maxrss) = unsafe {
	let mut usage = std::mem::zeroed();
	let _ = libc::getrusage(libc::RUSAGE_SELF, &mut usage);
	(usage.ru_utime, usage.ru_stime, usage.ru_maxrss)
	};
	eprintln!(
	"user time: {} s",
	utime.tv_sec as f64 + utime.tv_usec as f64 / 1_000_000f64
	);
	eprintln!(
	"system time: {} s",
	stime.tv_sec as f64 + stime.tv_usec as f64 / 1_000_000f64
	);
	eprintln!("maximum rss: {} KB", maxrss);
	}
	}
	}

Do we just need to mention that this lack of support also applies to wasm targets here, or is there more information that we could or should be providing?

I'm looking for ways to contribute and this issue seemed like a decent place to start.

[lu-zero]

if your wasm target supports getrusage it could be reported instead. I'd replace the message with "resource usage report is not supported on this platform" or such.