Auto merge of rust-lang#3290 - devnexen:android_unlocked_io_api, r=JohnTitor

android add handful lock free stdio calls

Author: bors

libc-test/build.rs

@@ -1908,6 +1908,8 @@ fn test_android(target: &str) {
 
             // Added in API level 28, but some tests use level 24.
             "pthread_attr_getinheritsched" | "pthread_attr_setinheritsched" => true,
+            // Added in API level 28, but some tests use level 24.
+            "fread_unlocked" | "fwrite_unlocked" | "fgets_unlocked" | "fflush_unlocked" => true,
 
             _ => false,
         }

libc-test/semver/android.txt

@@ -3101,6 +3101,7 @@ ff_trigger
 fgetc
 fgetpos
 fgets
+fgets_unlocked
 fgetxattr
 fileno
 flistxattr
@@ -3116,6 +3117,7 @@ fprintf
 fputc
 fputs
 fread
+fread_unlocked
 free
 freeaddrinfo
 freeifaddrs
@@ -3144,6 +3146,7 @@ ftruncate
 ftruncate64
 futimens
 fwrite
+fwrite_unlocked
 gai_strerror
 genlmsghdr
 getaddrinfo

src/unix/linux_like/android/mod.rs

@@ -3708,6 +3708,20 @@ extern "C" {
         needle: *const ::c_void,
         needlelen: ::size_t,
     ) -> *mut ::c_void;
+    pub fn fread_unlocked(
+        buf: *mut ::c_void,
+        size: ::size_t,
+        nobj: ::size_t,
+        stream: *mut ::FILE,
+    ) -> ::size_t;
+    pub fn fwrite_unlocked(
+        buf: *const ::c_void,
+        size: ::size_t,
+        nobj: ::size_t,
+        stream: *mut ::FILE,
+    ) -> ::size_t;
+    pub fn fflush_unlocked(stream: *mut ::FILE) -> ::c_int;
+    pub fn fgets_unlocked(buf: *mut ::c_char, size: ::c_int, stream: *mut ::FILE) -> *mut ::c_char;
 }
 
 cfg_if! {

src/unix/linux_like/linux/mod.rs

@@ -4773,7 +4773,7 @@ extern "C" {
         newfd: ::c_int,
     ) -> ::c_int;
     pub fn fread_unlocked(
-        ptr: *mut ::c_void,
+        buf: *mut ::c_void,
         size: ::size_t,
         nobj: ::size_t,
         stream: *mut ::FILE,