musl: Fix the value of CPU_SETSIZE on musl 1.2+

Link: https://github.com/kraj/musl/blob/ff441c9ddfefbb94e5881ddd5112b24a944dc36c/include/sched.h#L126

Author: tgross35

src/unix/linux_like/linux/musl/mod.rs

@@ -584,11 +584,8 @@ pub const __SIZEOF_PTHREAD_MUTEXATTR_T: usize = 4;
 pub const __SIZEOF_PTHREAD_RWLOCKATTR_T: usize = 8;
 pub const __SIZEOF_PTHREAD_BARRIERATTR_T: usize = 4;
 
-// FIXME(musl): Value is 1024 for all architectures since 1.2.4
-#[cfg(not(target_arch = "loongarch64"))]
-pub const CPU_SETSIZE: c_int = 128;
-#[cfg(target_arch = "loongarch64")]
-pub const CPU_SETSIZE: c_int = 1024;
+// Value was changed in 1.2.4
+pub const CPU_SETSIZE: c_int = if cfg!(musl_v1_2_3) { 1024 } else { 128 };
 
 pub const PTRACE_TRACEME: c_int = 0;
 pub const PTRACE_PEEKTEXT: c_int = 1;