Implement max_align_t

43 files changed, 262 insertions, 24 deletions

diff --git a/ci/azure.yml b/ci/azure.yml
index 456ac7f74f..97f13c9da3 100644
--- a/ci/azure.yml
+++ b/ci/azure.yml
@@ -25,7 +25,7 @@ jobs:
           TARGET: x86_64-unknown-linux-gnu
 
   - job: DockerLinuxTier2
-    dependsOn: DockerLinuxTier1
+    #dependsOn: DockerLinuxTier1
     pool:
       vmImage: ubuntu-16.04
     steps:
diff --git a/libc-test/build.rs b/libc-test/build.rs
index 9eb83e85e1..861fc21b09 100644
--- a/libc-test/build.rs
+++ b/libc-test/build.rs
@@ -31,6 +31,23 @@ fn do_ctest() {
     }
 }
 
+fn ctest_cfg() -> ctest::TestGenerator {
+    let mut cfg = ctest::TestGenerator::new();
+    let libc_cfgs = [
+        "libc_priv_mod_use",
+        "libc_union",
+        "libc_const_size_of",
+        "libc_align",
+        "libc_core_cvoid",
+        "libc_packedN",
+        "libc_thread_local",
+    ];
+    for f in &libc_cfgs {
+        cfg.cfg(f, None);
+    }
+    cfg
+}
+
 fn main() {
     do_cc();
     do_ctest();
@@ -59,8 +76,9 @@ macro_rules! headers {
 fn test_apple(target: &str) {
     assert!(target.contains("apple"));
     let x86_64 = target.contains("x86_64");
+    let i686 = target.contains("i686");
 
-    let mut cfg = ctest::TestGenerator::new();
+    let mut cfg = ctest_cfg();
     cfg.flag("-Wno-deprecated-declarations");
     cfg.define("__APPLE_USE_RFC_3542", None);
 
@@ -225,13 +243,18 @@ fn test_apple(target: &str) {
         }
     });
 
+    cfg.skip_roundtrip(move |s| match s {
+        // FIXME: this type has the wrong ABI
+        "max_align_t" if i686 => true,
+        _ => false,
+    });
     cfg.generate("../src/lib.rs", "main.rs");
 }
 
 fn test_openbsd(target: &str) {
     assert!(target.contains("openbsd"));
 
-    let mut cfg = ctest::TestGenerator::new();
+    let mut cfg = ctest_cfg();
     cfg.flag("-Wno-deprecated-declarations");
 
     headers! { cfg:
@@ -371,7 +394,7 @@ fn test_windows(target: &str) {
     assert!(target.contains("windows"));
     let gnu = target.contains("gnu");
 
-    let mut cfg = ctest::TestGenerator::new();
+    let mut cfg = ctest_cfg();
     cfg.define("_WIN32_WINNT", Some("0x8000"));
 
     headers! { cfg:
@@ -474,7 +497,7 @@ fn test_windows(target: &str) {
 fn test_redox(target: &str) {
     assert!(target.contains("redox"));
 
-    let mut cfg = ctest::TestGenerator::new();
+    let mut cfg = ctest_cfg();
     cfg.flag("-Wno-deprecated-declarations");
 
     headers! {
@@ -540,7 +563,7 @@ fn test_redox(target: &str) {
 fn test_cloudabi(target: &str) {
     assert!(target.contains("cloudabi"));
 
-    let mut cfg = ctest::TestGenerator::new();
+    let mut cfg = ctest_cfg();
     cfg.flag("-Wno-deprecated-declarations");
 
     headers! {
@@ -611,7 +634,7 @@ fn test_cloudabi(target: &str) {
 fn test_solaris(target: &str) {
     assert!(target.contains("solaris"));
 
-    let mut cfg = ctest::TestGenerator::new();
+    let mut cfg = ctest_cfg();
     cfg.flag("-Wno-deprecated-declarations");
 
     cfg.define("_XOPEN_SOURCE", Some("700"));
@@ -722,7 +745,7 @@ fn test_solaris(target: &str) {
 fn test_netbsd(target: &str) {
     assert!(target.contains("netbsd"));
     let rumprun = target.contains("rumprun");
-    let mut cfg = ctest::TestGenerator::new();
+    let mut cfg = ctest_cfg();
 
     cfg.flag("-Wno-deprecated-declarations");
     cfg.define("_NETBSD_SOURCE", Some("1"));
@@ -922,7 +945,7 @@ fn test_netbsd(target: &str) {
 
 fn test_dragonflybsd(target: &str) {
     assert!(target.contains("dragonfly"));
-    let mut cfg = ctest::TestGenerator::new();
+    let mut cfg = ctest_cfg();
     cfg.flag("-Wno-deprecated-declarations");
 
     headers! {
@@ -1127,7 +1150,7 @@ fn test_dragonflybsd(target: &str) {
 fn test_wasi(target: &str) {
     assert!(target.contains("wasi"));
 
-    let mut cfg = ctest::TestGenerator::new();
+    let mut cfg = ctest_cfg();
     cfg.define("_GNU_SOURCE", None);
 
     headers! { cfg:
@@ -1204,7 +1227,7 @@ fn test_android(target: &str) {
     };
     let x86 = target.contains("i686") || target.contains("x86_64");
 
-    let mut cfg = ctest::TestGenerator::new();
+    let mut cfg = ctest_cfg();
     cfg.define("_GNU_SOURCE", None);
 
     headers! { cfg:
@@ -1429,7 +1452,7 @@ fn test_android(target: &str) {
 
 fn test_freebsd(target: &str) {
     assert!(target.contains("freebsd"));
-    let mut cfg = ctest::TestGenerator::new();
+    let mut cfg = ctest_cfg();
 
     let freebsd_ver = which_freebsd();
 
@@ -1631,7 +1654,7 @@ fn test_freebsd(target: &str) {
 fn test_emscripten(target: &str) {
     assert!(target.contains("emscripten"));
 
-    let mut cfg = ctest::TestGenerator::new();
+    let mut cfg = ctest_cfg();
     cfg.define("_GNU_SOURCE", None); // FIXME: ??
 
     headers! { cfg:
@@ -1852,17 +1875,19 @@ fn test_linux(target: &str) {
     }
 
     let arm = target.contains("arm");
-    let x86_64 = target.contains("x86_64");
-    let x86_32 = target.contains("i686");
-    let x32 = target.contains("x32");
+    let i686 = target.contains("i686");
     let mips = target.contains("mips");
     let mips32 = mips && !target.contains("64");
-    let mips64 = mips && target.contains("64");
     let mips32_musl = mips32 && musl;
-    let sparc64 = target.contains("sparc64");
+    let mips64 = mips && target.contains("64");
+    let ppc64 = target.contains("powerpc64");
     let s390x = target.contains("s390x");
+    let sparc64 = target.contains("sparc64");
+    let x32 = target.contains("x32");
+    let x86_32 = target.contains("i686");
+    let x86_64 = target.contains("x86_64");
 
-    let mut cfg = ctest::TestGenerator::new();
+    let mut cfg = ctest_cfg();
     cfg.define("_GNU_SOURCE", None);
     // This macro re-deifnes fscanf,scanf,sscanf to link to the symbols that are
     // deprecated since glibc >= 2.29. This allows Rust binaries to link against
@@ -2286,6 +2311,9 @@ fn test_linux(target: &str) {
             true
         }
 
+        // FIXME: the call ABI of max_align_t is incorrect on these platforms:
+        "max_align_t" if i686 || mips64 || ppc64 => true,
+
         _ => false,
     });
 
@@ -2305,7 +2333,7 @@ fn test_linux_like_apis(target: &str) {
 
     if linux || android || emscripten {
         // test strerror_r from the `string.h` header
-        let mut cfg = ctest::TestGenerator::new();
+        let mut cfg = ctest_cfg();
         cfg.skip_type(|_| true).skip_static(|_| true);
 
         headers! { cfg: "string.h" }
@@ -2321,7 +2349,7 @@ fn test_linux_like_apis(target: &str) {
     if linux || android || emscripten {
         // test fcntl - see:
         // http://man7.org/linux/man-pages/man2/fcntl.2.html
-        let mut cfg = ctest::TestGenerator::new();
+        let mut cfg = ctest_cfg();
 
         if musl {
             cfg.header("fcntl.h");
@@ -2351,7 +2379,7 @@ fn test_linux_like_apis(target: &str) {
 
     if linux || android {
         // test termios
-        let mut cfg = ctest::TestGenerator::new();
+        let mut cfg = ctest_cfg();
         cfg.header("asm/termbits.h");
         cfg.skip_type(|_| true)
             .skip_static(|_| true)
@@ -2368,7 +2396,7 @@ fn test_linux_like_apis(target: &str) {
 
     if linux || android {
         // test IPV6_ constants:
-        let mut cfg = ctest::TestGenerator::new();
+        let mut cfg = ctest_cfg();
         headers! {
             cfg:
             "linux/in6.h"
@@ -2399,7 +2427,7 @@ fn test_linux_like_apis(target: &str) {
         // These types have a field called `p_type`, but including
         // "resolve.h" defines a `p_type` macro that expands to `__p_type`
         // making the tests for these fails when both are included.
-        let mut cfg = ctest::TestGenerator::new();
+        let mut cfg = ctest_cfg();
         cfg.header("elf.h");
         cfg.skip_fn(|_| true)
             .skip_static(|_| true)
diff --git a/src/unix/bsd/apple/b32/align.rs b/src/unix/bsd/apple/b32/align.rs
new file mode 100644
index 0000000000..ba9bc3ab3e
--- /dev/null
+++ b/src/unix/bsd/apple/b32/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(16))]
+pub struct max_align_t([f64; 2]);
diff --git a/src/unix/bsd/apple/b32.rs b/src/unix/bsd/apple/b32/mod.rs
index eacb0307cc..9248e3adf2 100644
--- a/src/unix/bsd/apple/b32.rs
+++ b/src/unix/bsd/apple/b32/mod.rs
@@ -106,3 +106,10 @@ extern "C" {
         options: ::c_ulong,
     ) -> ::c_int;
 }
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/bsd/apple/b64/align.rs b/src/unix/bsd/apple/b64/align.rs
new file mode 100644
index 0000000000..ba9bc3ab3e
--- /dev/null
+++ b/src/unix/bsd/apple/b64/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(16))]
+pub struct max_align_t([f64; 2]);
diff --git a/src/unix/bsd/apple/b64.rs b/src/unix/bsd/apple/b64/mod.rs
index 9019babc7c..7f7008387b 100644
--- a/src/unix/bsd/apple/b64.rs
+++ b/src/unix/bsd/apple/b64/mod.rs
@@ -111,3 +111,10 @@ extern "C" {
         options: ::c_uint,
     ) -> ::c_int;
 }
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/bsd/freebsdlike/freebsd/x86_64/align.rs b/src/unix/bsd/freebsdlike/freebsd/x86_64/align.rs
new file mode 100644
index 0000000000..7fffedbf96
--- /dev/null
+++ b/src/unix/bsd/freebsdlike/freebsd/x86_64/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(16))]
+pub struct max_align_t([f64; 4]);
diff --git a/src/unix/bsd/freebsdlike/freebsd/x86_64.rs b/src/unix/bsd/freebsdlike/freebsd/x86_64/mod.rs
index 5220cde915..0769a22f88 100644
--- a/src/unix/bsd/freebsdlike/freebsd/x86_64.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/x86_64/mod.rs
@@ -15,3 +15,10 @@ cfg_if! {
     }
 }
 pub const MAP_32BIT: ::c_int = 0x00080000;
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/linux_like/android/b32/x86/align.rs b/src/unix/linux_like/android/b32/x86/align.rs
new file mode 100644
index 0000000000..ca2085497c
--- /dev/null
+++ b/src/unix/linux_like/android/b32/x86/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(8))]
+pub struct max_align_t([f64; 2]);
diff --git a/src/unix/linux_like/android/b32/x86.rs b/src/unix/linux_like/android/b32/x86/mod.rs
index a56fa00454..101bf2d51a 100644
--- a/src/unix/linux_like/android/b32/x86.rs
+++ b/src/unix/linux_like/android/b32/x86/mod.rs
@@ -413,3 +413,10 @@ pub const CS: ::c_int = 13;
 pub const EFL: ::c_int = 14;
 pub const UESP: ::c_int = 15;
 pub const SS: ::c_int = 16;
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/linux_like/android/b64/aarch64/align.rs b/src/unix/linux_like/android/b64/aarch64/align.rs
new file mode 100644
index 0000000000..a71235ab29
--- /dev/null
+++ b/src/unix/linux_like/android/b64/aarch64/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(16))]
+pub struct max_align_t([f32; 8]);
diff --git a/src/unix/linux_like/android/b64/aarch64.rs b/src/unix/linux_like/android/b64/aarch64/mod.rs
index cb1c81b260..b2b91889a2 100644
--- a/src/unix/linux_like/android/b64/aarch64.rs
+++ b/src/unix/linux_like/android/b64/aarch64/mod.rs
@@ -323,3 +323,10 @@ pub const SYS_pkey_mprotect: ::c_long = 288;
 pub const SYS_pkey_alloc: ::c_long = 289;
 pub const SYS_pkey_free: ::c_long = 290;
 pub const SYS_syscalls: ::c_long = 292;
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/linux_like/android/b64/x86_64/align.rs b/src/unix/linux_like/android/b64/x86_64/align.rs
new file mode 100644
index 0000000000..7fffedbf96
--- /dev/null
+++ b/src/unix/linux_like/android/b64/x86_64/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(16))]
+pub struct max_align_t([f64; 4]);
diff --git a/src/unix/linux_like/android/b64/x86_64.rs b/src/unix/linux_like/android/b64/x86_64/mod.rs
index 2ab6080a6d..f5b8b16ea3 100644
--- a/src/unix/linux_like/android/b64/x86_64.rs
+++ b/src/unix/linux_like/android/b64/x86_64/mod.rs
@@ -418,3 +418,10 @@ pub const DS: ::c_int = 23;
 pub const ES: ::c_int = 24;
 pub const FS: ::c_int = 25;
 pub const GS: ::c_int = 26;
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/linux_like/emscripten/align.rs b/src/unix/linux_like/emscripten/align.rs
index 8019b7c3bb..8fa2186fc9 100644
--- a/src/unix/linux_like/emscripten/align.rs
+++ b/src/unix/linux_like/emscripten/align.rs
@@ -1,5 +1,9 @@
 macro_rules! expand_align {
     () => {
+        #[derive(Copy, Clone, Debug, PartialEq)]
+        #[repr(C, align(8))]
+        pub struct max_align_t([f64; 2]);
+
         s! {
             #[repr(align(4))]
             pub struct pthread_mutex_t {
diff --git a/src/unix/linux_like/linux/gnu/b32/arm/align.rs b/src/unix/linux_like/linux/gnu/b32/arm/align.rs
new file mode 100644
index 0000000000..cd887aca9d
--- /dev/null
+++ b/src/unix/linux_like/linux/gnu/b32/arm/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(8))]
+pub struct max_align_t([i64; 2]);
diff --git a/src/unix/linux_like/linux/gnu/b32/arm.rs b/src/unix/linux_like/linux/gnu/b32/arm/mod.rs
index 73af4b8116..f74b41e315 100644
--- a/src/unix/linux_like/linux/gnu/b32/arm.rs
+++ b/src/unix/linux_like/linux/gnu/b32/arm/mod.rs
@@ -859,3 +859,10 @@ pub const SYS_pkey_mprotect: ::c_long = 394;
 pub const SYS_pkey_alloc: ::c_long = 395;
 pub const SYS_pkey_free: ::c_long = 396;
 pub const SYS_statx: ::c_long = 397;
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/linux_like/linux/gnu/b32/mips/align.rs b/src/unix/linux_like/linux/gnu/b32/mips/align.rs
new file mode 100644
index 0000000000..a6e238d778
--- /dev/null
+++ b/src/unix/linux_like/linux/gnu/b32/mips/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(8))]
+pub struct max_align_t([f32; 4]);
diff --git a/src/unix/linux_like/linux/gnu/b32/mips.rs b/src/unix/linux_like/linux/gnu/b32/mips/mod.rs
index cfe8ef6927..23b0160bff 100644
--- a/src/unix/linux_like/linux/gnu/b32/mips.rs
+++ b/src/unix/linux_like/linux/gnu/b32/mips/mod.rs
@@ -891,3 +891,10 @@ pub const TIOCM_RNG: ::c_int = 0x200;
 pub const TIOCM_DSR: ::c_int = 0x400;
 
 pub const EHWPOISON: ::c_int = 168;
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/linux_like/linux/gnu/b32/x86/align.rs b/src/unix/linux_like/linux/gnu/b32/x86/align.rs
new file mode 100644
index 0000000000..c9ab8b9784
--- /dev/null
+++ b/src/unix/linux_like/linux/gnu/b32/x86/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(16))]
+pub struct max_align_t([f64; 6]);
diff --git a/src/unix/linux_like/linux/gnu/b32/x86.rs b/src/unix/linux_like/linux/gnu/b32/x86/mod.rs
index 67b80b28f7..05e876067d 100644
--- a/src/unix/linux_like/linux/gnu/b32/x86.rs
+++ b/src/unix/linux_like/linux/gnu/b32/x86/mod.rs
@@ -1147,3 +1147,10 @@ extern "C" {
         ucp: *const ucontext_t,
     ) -> ::c_int;
 }
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/linux_like/linux/gnu/b64/aarch64/align.rs b/src/unix/linux_like/linux/gnu/b64/aarch64/align.rs
new file mode 100644
index 0000000000..a71235ab29
--- /dev/null
+++ b/src/unix/linux_like/linux/gnu/b64/aarch64/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(16))]
+pub struct max_align_t([f32; 8]);
diff --git a/src/unix/linux_like/linux/gnu/b64/aarch64.rs b/src/unix/linux_like/linux/gnu/b64/aarch64/mod.rs
index 4769e74e7b..b980a11b19 100644
--- a/src/unix/linux_like/linux/gnu/b64/aarch64.rs
+++ b/src/unix/linux_like/linux/gnu/b64/aarch64/mod.rs
@@ -936,3 +936,10 @@ extern "C" {
         newlen: ::size_t,
     ) -> ::c_int;
 }
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/linux_like/linux/gnu/b64/mips64/align.rs b/src/unix/linux_like/linux/gnu/b64/mips64/align.rs
new file mode 100644
index 0000000000..7fffedbf96
--- /dev/null
+++ b/src/unix/linux_like/linux/gnu/b64/mips64/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(16))]
+pub struct max_align_t([f64; 4]);
diff --git a/src/unix/linux_like/linux/gnu/b64/mips64.rs b/src/unix/linux_like/linux/gnu/b64/mips64/mod.rs
index a9b49f3c31..5b3da3cb2d 100644
--- a/src/unix/linux_like/linux/gnu/b64/mips64.rs
+++ b/src/unix/linux_like/linux/gnu/b64/mips64/mod.rs
@@ -999,3 +999,10 @@ extern "C" {
         newlen: ::size_t,
     ) -> ::c_int;
 }
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/linux_like/linux/gnu/b64/powerpc64/align.rs b/src/unix/linux_like/linux/gnu/b64/powerpc64/align.rs
new file mode 100644
index 0000000000..86a5f28f1f
--- /dev/null
+++ b/src/unix/linux_like/linux/gnu/b64/powerpc64/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(16))]
+pub struct max_align_t([i64; 4]);
diff --git a/src/unix/linux_like/linux/gnu/b64/powerpc64.rs b/src/unix/linux_like/linux/gnu/b64/powerpc64/mod.rs
index 212062b32a..bd9089543a 100644
--- a/src/unix/linux_like/linux/gnu/b64/powerpc64.rs
+++ b/src/unix/linux_like/linux/gnu/b64/powerpc64/mod.rs
@@ -1035,3 +1035,10 @@ extern "C" {
         newlen: ::size_t,
     ) -> ::c_int;
 }
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/linux_like/linux/gnu/b64/sparc64/align.rs b/src/unix/linux_like/linux/gnu/b64/sparc64/align.rs
new file mode 100644
index 0000000000..86a5f28f1f
--- /dev/null
+++ b/src/unix/linux_like/linux/gnu/b64/sparc64/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(16))]
+pub struct max_align_t([i64; 4]);
diff --git a/src/unix/linux_like/linux/gnu/b64/sparc64.rs b/src/unix/linux_like/linux/gnu/b64/sparc64/mod.rs
index 32489bc33a..93b1fa5349 100644
--- a/src/unix/linux_like/linux/gnu/b64/sparc64.rs
+++ b/src/unix/linux_like/linux/gnu/b64/sparc64/mod.rs
@@ -970,3 +970,10 @@ extern "C" {
         newlen: ::size_t,
     ) -> ::c_int;
 }
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/linux_like/linux/gnu/b64/x86_64/align.rs b/src/unix/linux_like/linux/gnu/b64/x86_64/align.rs
new file mode 100644
index 0000000000..7fffedbf96
--- /dev/null
+++ b/src/unix/linux_like/linux/gnu/b64/x86_64/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(16))]
+pub struct max_align_t([f64; 4]);
diff --git a/src/unix/linux_like/linux/gnu/b64/x86_64/mod.rs b/src/unix/linux_like/linux/gnu/b64/x86_64/mod.rs
index 2ff0969b0a..d1a2294380 100644
--- a/src/unix/linux_like/linux/gnu/b64/x86_64/mod.rs
+++ b/src/unix/linux_like/linux/gnu/b64/x86_64/mod.rs
@@ -906,3 +906,10 @@ cfg_if! {
         pub use self::not_x32::*;
     }
 }
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/linux_like/linux/musl/b32/arm/align.rs b/src/unix/linux_like/linux/musl/b32/arm/align.rs
new file mode 100644
index 0000000000..6b5d118201
--- /dev/null
+++ b/src/unix/linux_like/linux/musl/b32/arm/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(8))]
+pub struct max_align_t(i64, i64);
diff --git a/src/unix/linux_like/linux/musl/b32/arm.rs b/src/unix/linux_like/linux/musl/b32/arm/mod.rs
index 12e977a64e..fd1e259fc3 100644
--- a/src/unix/linux_like/linux/musl/b32/arm.rs
+++ b/src/unix/linux_like/linux/musl/b32/arm/mod.rs
@@ -835,3 +835,10 @@ extern "C" {
         flags: ::c_uint,
     ) -> ::ssize_t;
 }
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/linux_like/linux/musl/b32/mips/align.rs b/src/unix/linux_like/linux/musl/b32/mips/align.rs
new file mode 100644
index 0000000000..a6e238d778
--- /dev/null
+++ b/src/unix/linux_like/linux/musl/b32/mips/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(8))]
+pub struct max_align_t([f32; 4]);
diff --git a/src/unix/linux_like/linux/musl/b32/mips.rs b/src/unix/linux_like/linux/musl/b32/mips/mod.rs
index f574223f9b..7fdd121a7a 100644
--- a/src/unix/linux_like/linux/musl/b32/mips.rs
+++ b/src/unix/linux_like/linux/musl/b32/mips/mod.rs
@@ -836,3 +836,10 @@ pub const SYS_mlock2: ::c_long = 4000 + 359;
 pub const SYS_copy_file_range: ::c_long = 4000 + 360;
 pub const SYS_preadv2: ::c_long = 4000 + 361;
 pub const SYS_pwritev2: ::c_long = 4000 + 362;
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/linux_like/linux/musl/b32/x86/align.rs b/src/unix/linux_like/linux/musl/b32/x86/align.rs
new file mode 100644
index 0000000000..b203d7e8c8
--- /dev/null
+++ b/src/unix/linux_like/linux/musl/b32/x86/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(8))]
+pub struct max_align_t([f64; 3]);
diff --git a/src/unix/linux_like/linux/musl/b32/x86.rs b/src/unix/linux_like/linux/musl/b32/x86/mod.rs
index de73b3ebc6..fb5569200c 100644
--- a/src/unix/linux_like/linux/musl/b32/x86.rs
+++ b/src/unix/linux_like/linux/musl/b32/x86/mod.rs
@@ -943,3 +943,10 @@ extern "C" {
         flags: ::c_uint,
     ) -> ::ssize_t;
 }
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/linux_like/linux/musl/b64/aarch64/align.rs b/src/unix/linux_like/linux/musl/b64/aarch64/align.rs
new file mode 100644
index 0000000000..a71235ab29
--- /dev/null
+++ b/src/unix/linux_like/linux/musl/b64/aarch64/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(16))]
+pub struct max_align_t([f32; 8]);
diff --git a/src/unix/linux_like/linux/musl/b64/aarch64.rs b/src/unix/linux_like/linux/musl/b64/aarch64/mod.rs
index caf49ff4ad..8c286d83cc 100644
--- a/src/unix/linux_like/linux/musl/b64/aarch64.rs
+++ b/src/unix/linux_like/linux/musl/b64/aarch64/mod.rs
@@ -645,3 +645,10 @@ pub const TIOCM_RI: ::c_int = TIOCM_RNG;
 extern "C" {
     pub fn ioctl(fd: ::c_int, request: ::c_int, ...) -> ::c_int;
 }
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/unix/linux_like/linux/musl/b64/x86_64/align.rs b/src/unix/linux_like/linux/musl/b64/x86_64/align.rs
new file mode 100644
index 0000000000..7fffedbf96
--- /dev/null
+++ b/src/unix/linux_like/linux/musl/b64/x86_64/align.rs
@@ -0,0 +1,3 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(C, align(16))]
+pub struct max_align_t([f64; 4]);
diff --git a/src/unix/linux_like/linux/musl/b64/x86_64.rs b/src/unix/linux_like/linux/musl/b64/x86_64/mod.rs
index 9e5a8bf1e9..e4741a3a19 100644
--- a/src/unix/linux_like/linux/musl/b64/x86_64.rs
+++ b/src/unix/linux_like/linux/musl/b64/x86_64/mod.rs
@@ -917,3 +917,10 @@ pub const TIOCM_RI: ::c_int = TIOCM_RNG;
 extern "C" {
     pub fn ioctl(fd: ::c_int, request: ::c_int, ...) -> ::c_int;
 }
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}
diff --git a/src/windows/gnu/align.rs b/src/windows/gnu/align.rs
new file mode 100644
index 0000000000..dd3a3f72d3
--- /dev/null
+++ b/src/windows/gnu/align.rs
@@ -0,0 +1,9 @@
+cfg_if! {
+    if #[cfg(target_pointer_width = "64")] {
+        #[derive(Copy, Clone, Debug, PartialEq)]
+        #[repr(C, align(16))] pub struct max_align_t([f64; 4]);
+    } else if #[cfg(target_pointer_width = "32")] {
+        #[derive(Copy, Clone, Debug, PartialEq)]
+        #[repr(C, align(16))] pub struct max_align_t([i64; 6]);
+    }
+}
diff --git a/src/windows/gnu.rs b/src/windows/gnu/mod.rs
index d6736d87c2..e74628b981 100644
--- a/src/windows/gnu.rs
+++ b/src/windows/gnu/mod.rs
@@ -14,3 +14,10 @@ extern "C" {
         n: ::size_t,
     ) -> ::c_int;
 }
+
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}