Auto merge of #2082 - landfillbaby:patch-1, r=Amanieu

use GNU/Linux siginfo_t on Android

Bionic uses an unchanged siginfo.h from the upstream linux so why not? :)
I literally just copied everything with siginfo_t from unix/linux_like/linux/gnu/mod.rs to unix/linux_like/android/mod.rs

src/unix/linux_like/android/mod.rs

@@ -2824,6 +2824,17 @@ cfg_if! {
 }
 
 impl siginfo_t {
+    pub unsafe fn si_addr(&self) -> *mut ::c_void {
+        #[repr(C)]
+        struct siginfo_sigfault {
+            _si_signo: ::c_int,
+            _si_errno: ::c_int,
+            _si_code: ::c_int,
+            si_addr: *mut ::c_void,
+        }
+        (*(self as *const siginfo_t as *const siginfo_sigfault)).si_addr
+    }
+
     pub unsafe fn si_value(&self) -> ::sigval {
         #[repr(C)]
         struct siginfo_timer {
@@ -2837,3 +2848,65 @@ impl siginfo_t {
         (*(self as *const siginfo_t as *const siginfo_timer)).si_sigval
     }
 }
+
+cfg_if! {
+    if #[cfg(libc_union)] {
+        // Internal, for casts to access union fields
+        #[repr(C)]
+        struct sifields_sigchld {
+            si_pid: ::pid_t,
+            si_uid: ::uid_t,
+            si_status: ::c_int,
+            si_utime: ::c_long,
+            si_stime: ::c_long,
+        }
+        impl ::Copy for sifields_sigchld {}
+        impl ::Clone for sifields_sigchld {
+            fn clone(&self) -> sifields_sigchld {
+                *self
+            }
+        }
+
+        // Internal, for casts to access union fields
+        #[repr(C)]
+        union sifields {
+            _align_pointer: *mut ::c_void,
+            sigchld: sifields_sigchld,
+        }
+
+        // Internal, for casts to access union fields. Note that some variants
+        // of sifields start with a pointer, which makes the alignment of
+        // sifields vary on 32-bit and 64-bit architectures.
+        #[repr(C)]
+        struct siginfo_f {
+            _siginfo_base: [::c_int; 3],
+            sifields: sifields,
+        }
+
+        impl siginfo_t {
+            unsafe fn sifields(&self) -> &sifields {
+                &(*(self as *const siginfo_t as *const siginfo_f)).sifields
+            }
+
+            pub unsafe fn si_pid(&self) -> ::pid_t {
+                self.sifields().sigchld.si_pid
+            }
+
+            pub unsafe fn si_uid(&self) -> ::uid_t {
+                self.sifields().sigchld.si_uid
+            }
+
+            pub unsafe fn si_status(&self) -> ::c_int {
+                self.sifields().sigchld.si_status
+            }
+
+            pub unsafe fn si_utime(&self) -> ::c_long {
+                self.sifields().sigchld.si_utime
+            }
+
+            pub unsafe fn si_stime(&self) -> ::c_long {
+                self.sifields().sigchld.si_stime
+            }
+        }
+    }
+}