Create optionally-available __int128 typedefs and use them for ARM64 definitions.

This adds the following types to fixed_width_ints behind appropriate platform cfgs:

* __int128
* __int128_t
* __uint128
* __uint128_t

and user_fpsimd_struct to arm64 android and linux.

1 files changed, 10 insertions, 0 deletions

diff --git a/build.rs b/build.rs
index 61acba646d..47eef2f802 100644
--- a/build.rs
+++ b/build.rs
@@ -60,6 +60,11 @@ fn main() {
         println!("cargo:rustc-cfg=libc_align");
     }
 
+    // Rust >= 1.26 supports i128 and u128:
+    if rustc_minor_ver >= 26 || rustc_dep_of_std {
+        println!("cargo:rustc-cfg=libc_int128");
+    }
+
     // Rust >= 1.30 supports `core::ffi::c_void`, so libc can just re-export it.
     // Otherwise, it defines an incompatible type to retaining
     // backwards-compatibility.
@@ -82,6 +87,11 @@ fn main() {
         println!("cargo:rustc-cfg=libc_ptr_addr_of");
     }
 
+    // Rust >= 1.57.0 allows assert! (and panics in general) in constants.
+    if rustc_minor_ver >= 57 || rustc_dep_of_std {
+        println!("cargo:rustc-cfg=libc_const_assert");
+    }
+
     // #[thread_local] is currently unstable
     if rustc_dep_of_std {
         println!("cargo:rustc-cfg=libc_thread_local");