Enable clone3() syscall on sparc-linux and sparc64-linux

Starting with version 7.0, the Linux kernel gained support
for clone3() on SPARC. Thus, it can be enabled in libc now.

Author: glaubitz

libc-test/build.rs

@@ -4646,9 +4646,6 @@ fn test_linux(target: &str) {
             // FIXME(value): IPPROTO_MAX was increased in 5.6 for IPPROTO_MPTCP:
             "IPPROTO_MAX" => true,
 
-            // FIXME(linux): Not yet implemented on sparc64
-            "SYS_clone3" if sparc64 => true,
-
             // FIXME(linux): Requires >= 6.9 kernel headers.
             n if (arm || ppc32) && n.starts_with("FUTEX2_") => true,
 

src/unix/linux_like/linux/gnu/b32/sparc/mod.rs

@@ -849,7 +849,6 @@ pub const SYS_fsconfig: c_long = 431;
 pub const SYS_fsmount: c_long = 432;
 pub const SYS_fspick: c_long = 433;
 pub const SYS_pidfd_open: c_long = 434;
-// Reserved in the kernel, but not actually implemented yet
 pub const SYS_clone3: c_long = 435;
 pub const SYS_close_range: c_long = 436;
 pub const SYS_openat2: c_long = 437;

src/unix/linux_like/linux/gnu/b64/sparc64/mod.rs

@@ -904,7 +904,6 @@ pub const SYS_fsconfig: c_long = 431;
 pub const SYS_fsmount: c_long = 432;
 pub const SYS_fspick: c_long = 433;
 pub const SYS_pidfd_open: c_long = 434;
-// Reserved in the kernel, but not actually implemented yet
 pub const SYS_clone3: c_long = 435;
 pub const SYS_close_range: c_long = 436;
 pub const SYS_openat2: c_long = 437;