Declare setdomainname and getdomainname on Android.

Android [supports] `setdomainname` and `getdomainname` in API level 26.

[supports] https://github.com/aosp-google/bionic/blob/28f9101d76b709febe25977f98530d77580387d1/libc/include/unistd.h#L236

(backport <#4212>)
(cherry picked from commit 7e1b5b8)

Author: sunfishcode

libc-test/build.rs

@@ -2140,6 +2140,9 @@ fn test_android(target: &str) {
             // Added in API level 26, but some tests use level 24.
             "endgrent" => true,
 
+            // Added in API level 26, but some tests use level 24.
+            "getdomainname" | "setdomainname" => true,
+
             // FIXME: bad function pointers:
             "isalnum" | "isalpha" | "iscntrl" | "isdigit" | "isgraph" | "islower" | "isprint"
             | "ispunct" | "isspace" | "isupper" | "isxdigit" | "isblank" | "tolower"

libc-test/semver/android.txt

@@ -3324,6 +3324,7 @@ getaddrinfo
 getchar
 getchar_unlocked
 getcwd
+getdomainname
 getegid
 getenv
 geteuid
@@ -3720,6 +3721,7 @@ sendmsg
 sendto
 servent
 setbuf
+setdomainname
 setegid
 setenv
 seteuid

src/unix/linux_like/android/mod.rs

@@ -4126,6 +4126,9 @@ extern "C" {
         newpath: *const c_char,
         flags: c_uint,
     ) -> c_int;
+
+    pub fn getdomainname(name: *mut c_char, len: size_t) -> c_int;
+    pub fn setdomainname(name: *const c_char, len: size_t) -> c_int;
 }
 
 cfg_if! {