adding preadv2/pwritev2 to linux musl (1.2.5 min.)

close rust-lang#3760

(apply <rust-lang#3762> to `main`)
[ resolve conflicts - Trevor ]
(cherry picked from commit 499ed57)

Author: dcarlier

libc-test/build.rs

@@ -4311,6 +4311,9 @@ fn test_linux(target: &str) {
             // FIXME: function pointers changed since Ubuntu 23.10
             "strtol" | "strtoll" | "strtoul" | "strtoull" | "fscanf" | "scanf" | "sscanf" => true,
 
+            // Added in musl 1.2.5
+            "preadv2" | "pwritev2" if musl => true,
+
             _ => false,
         }
     });

libc-test/semver/linux-musl.txt

@@ -23,6 +23,11 @@ PF_XDP
 PIDFD_NONBLOCK
 PR_SET_VMA
 PR_SET_VMA_ANON_NAME
+RWF_APPEND
+RWF_DSYNC
+RWF_HIPRI
+RWF_NOWAIT
+RWF_SYNC
 SOL_XDP
 XDP_SHARED_UMEM
 XDP_COPY
@@ -75,12 +80,14 @@ getutxline
 lio_listio
 ntptimeval
 open_wmemstream
+preadv2
 preadv64
 prlimit
 prlimit64
 process_vm_readv
 process_vm_writev
 pututxline
+pwritev2
 pwritev64
 reallocarray
 setutxent

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

@@ -667,6 +667,12 @@ pub const PTRACE_PEEKSIGINFO: ::c_int = 0x4209;
 pub const PTRACE_GETSIGMASK: ::c_uint = 0x420a;
 pub const PTRACE_SETSIGMASK: ::c_uint = 0x420b;
 
+pub const RWF_HIPRI: ::c_int = 0x00000001;
+pub const RWF_DSYNC: ::c_int = 0x00000002;
+pub const RWF_SYNC: ::c_int = 0x00000004;
+pub const RWF_NOWAIT: ::c_int = 0x00000008;
+pub const RWF_APPEND: ::c_int = 0x00000010;
+
 pub const AF_IB: ::c_int = 27;
 pub const AF_MPLS: ::c_int = 28;
 pub const AF_NFC: ::c_int = 39;
@@ -857,6 +863,20 @@ extern "C" {
         dirfd: ::c_int,
         path: *const ::c_char,
     ) -> ::c_int;
+    pub fn preadv2(
+        fd: ::c_int,
+        iov: *const ::iovec,
+        iovcnt: ::c_int,
+        offset: ::off_t,
+        flags: ::c_int,
+    ) -> ::ssize_t;
+    pub fn pwritev2(
+        fd: ::c_int,
+        iov: *const ::iovec,
+        iovcnt: ::c_int,
+        offset: ::off_t,
+        flags: ::c_int,
+    ) -> ::ssize_t;
     pub fn getauxval(type_: ::c_ulong) -> ::c_ulong;
 
     // Added in `musl` 1.1.20