Fix MSRV on Windows

Author: JohnTitor

src/windows/msvc/x86_64.rs renamed to src/windows/msvc/x86_64/align.rs

@@ -63,7 +63,7 @@ s! {
         pub MxCsr_Mask: ::c_ulong,
         pub FloatRegisters: [M128A; 8],
         pub XmmRegisters: [M128A; 16],
-        _Reserved4: [::c_uchar; 96],
+        _Reserved4: [[::c_uchar; 16]; 6],
     }
 
     #[repr(align(16))]

src/windows/msvc/x86_64/mod.rs

@@ -0,0 +1,6 @@
+cfg_if! {
+    if #[cfg(libc_align)] {
+        mod align;
+        pub use self::align::*;
+    }
+}