linux: Correct the value of EPIOC[GS]PARAMS with nonstandard _IOC

PowerPC, Sparc, and MIPS (32- and 64-bit for all) have different `_IOC`
numbers, meaning the constants were inaccurate. Example error on
PowerPC64:

    bad `EPIOCSPARAMS` value at byte 4: rust: 64 (0x40) != c 128 (0x80)
        rust bytes: 00 00 00 00 40 08 8a 01
        c bytes:    00 00 00 00 80 08 8a 01
    bad `EPIOCGPARAMS` value at byte 4: rust: 128 (0x80) != c 64 (0x40)
        rust bytes: 00 00 00 00 80 08 8a 02
        c bytes:    00 00 00 00 40 08 8a 02

Resolve this by using `_IOW` and `_IOR`.

Source: https://github.com/torvalds/linux/blob/502d801f0ab03e4f32f9a33d203154ce84887921/include/uapi/linux/eventpoll.h#L97-L99
Fixes: fb58c01 ("epoll: add busy polling parameters")

Author: tgross35

libc-test/build.rs

@@ -3823,7 +3823,7 @@ fn test_linux(target: &str) {
     let mips64 = target.contains("mips64");
     let mips32 = mips && !mips64;
     let versions = &*VERSIONS;
-    let kernel = versions.linux.unwrap_or((0, 0));
+    let kernel = versions.linux.unwrap();
 
     let musl_v1_2_3 = env::var("CARGO_CFG_LIBC_UNSTABLE_MUSL_V1_2_3").is_ok();
     if musl_v1_2_3 {

src/unix/linux_like/linux/mod.rs

@@ -3649,8 +3649,9 @@ pub const SCHED_FLAG_ALL: c_int = SCHED_FLAG_RESET_ON_FORK
     | SCHED_FLAG_UTIL_CLAMP;
 
 // ioctl_eventpoll: added in Linux 6.9
-pub const EPIOCSPARAMS: Ioctl = 0x40088a01;
-pub const EPIOCGPARAMS: Ioctl = u32_cast_ioctl(0x80088a02);
+const EPOLL_IOC_TYPE: u32 = 0x8A;
+pub const EPIOCSPARAMS: Ioctl = _IOW::<epoll_params>(EPOLL_IOC_TYPE, 0x01);
+pub const EPIOCGPARAMS: Ioctl = _IOR::<epoll_params>(EPOLL_IOC_TYPE, 0x02);
 
 // siginfo.h
 pub const SI_DETHREAD: c_int = -7;