Auto merge of #1588 - oxalica:upgrade-musl, r=gnzlbg

Upgrade to musl 1.1.24 in CI

Required by #1577

Note that in musl 1.1.24, `struct sched_param` from `sched.h` has changed and some fields became reserved. So [these fields](https://github.com/rust-lang/libc/blob/13d4a5da2eafd82d3ebb2acb729d8b8c9148fb1f/src/unix/linux_like/mod.rs#L97) are outdated. I'm not sure if we should rename them, since they are in public API.

I simply skip `struct sched_param` from the test now.

Here's the diff between musl 1.1.23 and 1.1.24
```
diff --git a/include/sched.h b/include/sched.h
index 05d40b1e..7e470d3a 100644
--- a/include/sched.h
+++ b/include/sched.h
@@ -18,10 +18,12 @@ extern "C" {

 struct sched_param {
        int sched_priority;
-       int sched_ss_low_priority;
-       struct timespec sched_ss_repl_period;
-       struct timespec sched_ss_init_budget;
-       int sched_ss_max_repl;
+       int __reserved1;
+       struct {
+               time_t __reserved1;
+               long __reserved2;
+       } __reserved2[2];
+       int __reserved3;
 };
```

1 files changed, 15 insertions, 14 deletions

diff --git a/libc-test/build.rs b/libc-test/build.rs
index 22e61664a4..5840c7c3a5 100644
--- a/libc-test/build.rs
+++ b/libc-test/build.rs
@@ -2063,7 +2063,6 @@ fn test_linux(target: &str) {
     let i686 = target.contains("i686");
     let mips = target.contains("mips");
     let mips32 = mips && !target.contains("64");
-    let mips32_musl = mips32 && musl;
     let mips64 = mips && target.contains("64");
     let ppc64 = target.contains("powerpc64");
     let s390x = target.contains("s390x");
@@ -2071,6 +2070,7 @@ fn test_linux(target: &str) {
     let x32 = target.contains("x32");
     let x86_32 = target.contains("i686");
     let x86_64 = target.contains("x86_64");
+    let aarch64_musl = target.contains("aarch64") && musl;
 
     let mut cfg = ctest_cfg();
     cfg.define("_GNU_SOURCE", None);
@@ -2134,8 +2134,7 @@ fn test_linux(target: &str) {
                "sys/prctl.h",
                "sys/ptrace.h",
                "sys/quota.h",
-               // FIXME: the mips-musl CI build jobs use ancient musl 1.0.15:
-               [!mips32_musl]: "sys/random.h",
+               "sys/random.h",
                "sys/reboot.h",
                "sys/resource.h",
                "sys/sem.h",
@@ -2189,8 +2188,7 @@ fn test_linux(target: &str) {
         "linux/fs.h",
         "linux/futex.h",
         "linux/genetlink.h",
-        // FIXME: musl version 1.0.15 used by mips build jobs is ancient
-        [!mips32_musl]: "linux/if.h",
+        "linux/if.h",
         "linux/if_addr.h",
         "linux/if_alg.h",
         "linux/if_ether.h",
@@ -2307,9 +2305,6 @@ fn test_linux(target: &str) {
             // structs.
             "termios2" => true,
 
-            // FIXME: musl version using by mips build jobs 1.0.15 is ancient:
-            "ifmap" | "ifreq" | "ifconf" if mips32_musl => true,
-
             // FIXME: remove once Ubuntu 20.04 LTS is released, somewhere in 2020.
             // ucontext_t added a new field as of glibc 2.28; our struct definition is
             // conservative and omits the field, but that means the size doesn't match for newer
@@ -2353,7 +2348,7 @@ fn test_linux(target: &str) {
             // Require Linux kernel 5.1:
             "F_SEAL_FUTURE_WRITE" => true,
 
-            // The musl version 1.0.22 used in CI does not
+            // The musl version 1.1.24 used in CI does not
             // contain these glibc constants yet:
             | "RLIMIT_RTTIME" // should be in `resource.h`
             | "TCP_COOKIE_TRANSACTIONS"  // should be in the `netinet/tcp.h` header
@@ -2375,10 +2370,6 @@ fn test_linux(target: &str) {
             // - these constants are used by the glibc implementation.
             n if musl && n.contains("__SIZEOF_PTHREAD") => true,
 
-            // FIXME: musl version 1.0.15 used by mips build jobs is ancient
-            t if mips32_musl && t.starts_with("IFF") => true,
-            "MFD_HUGETLB" | "AF_XDP" | "PF_XDP" if mips32_musl => true,
-
             _ => false,
         }
     });
@@ -2462,7 +2453,17 @@ fn test_linux(target: &str) {
                                            field == "_pad2" ||
                                            field == "ssi_syscall" ||
                                            field == "ssi_call_addr" ||
-                                           field == "ssi_arch"))
+                                           field == "ssi_arch")) ||
+        // FIXME: After musl 1.1.24, it have only one field `sched_priority`,
+        // while other fields become reserved.
+        (struct_ == "sched_param" && [
+            "sched_ss_low_priority",
+            "sched_ss_repl_period",
+            "sched_ss_init_budget",
+            "sched_ss_max_repl",
+        ].contains(&field) && musl) ||
+        // FIXME: After musl 1.1.24, the type becomes `int` instead of `unsigned short`.
+        (struct_ == "ipc_perm" && field == "__seq" && aarch64_musl)
     });
 
     cfg.skip_roundtrip(move |s| match s {