Auto merge of #1621 - coolreader18:fdset-redox-ai-android, r=gnzlbg

Add Redox FD_* function-macros and Android AI_* constants

I'm not sure if I'm allowed to add multiple, separate APIs in the same PR, but I guess they're both for uncommon/exotic platforms?

The `AI_*` constants were taken from `usr/include/netdb.h` on my Termux install; the `FD_` functions were taken from `linux_like/mod.rs`.

src/unix/linux_like/android/mod.rs

@@ -1157,6 +1157,21 @@ pub const RTLD_NOLOAD: ::c_int = 0x4;
 
 pub const SEM_FAILED: *mut sem_t = 0 as *mut sem_t;
 
+pub const AI_PASSIVE: ::c_int = 0x00000001;
+pub const AI_CANONNAME: ::c_int = 0x00000002;
+pub const AI_NUMERICHOST: ::c_int = 0x00000004;
+pub const AI_NUMERICSERV: ::c_int = 0x00000008;
+pub const AI_MASK: ::c_int = AI_PASSIVE
+    | AI_CANONNAME
+    | AI_NUMERICHOST
+    | AI_NUMERICSERV
+    | AI_ADDRCONFIG;
+pub const AI_ALL: ::c_int = 0x00000100;
+pub const AI_V4MAPPED_CFG: ::c_int = 0x00000200;
+pub const AI_ADDRCONFIG: ::c_int = 0x00000400;
+pub const AI_V4MAPPED: ::c_int = 0x00000800;
+pub const AI_DEFAULT: ::c_int = AI_V4MAPPED_CFG | AI_ADDRCONFIG;
+
 pub const LINUX_REBOOT_MAGIC1: ::c_int = 0xfee1dead;
 pub const LINUX_REBOOT_MAGIC2: ::c_int = 672274793;
 pub const LINUX_REBOOT_MAGIC2A: ::c_int = 85072278;

src/unix/redox/mod.rs

@@ -839,6 +839,32 @@ f! {
     pub fn WCOREDUMP(status: ::c_int) -> bool {
         (status & 0x80) != 0
     }
+
+    pub fn FD_CLR(fd: ::c_int, set: *mut fd_set) -> () {
+        let fd = fd as usize;
+        let size = ::mem::size_of_val(&(*set).fds_bits[0]) * 8;
+        (*set).fds_bits[fd / size] &= !(1 << (fd % size));
+        return
+    }
+
+    pub fn FD_ISSET(fd: ::c_int, set: *mut fd_set) -> bool {
+        let fd = fd as usize;
+        let size = ::mem::size_of_val(&(*set).fds_bits[0]) * 8;
+        return ((*set).fds_bits[fd / size] & (1 << (fd % size))) != 0
+    }
+
+    pub fn FD_SET(fd: ::c_int, set: *mut fd_set) -> () {
+        let fd = fd as usize;
+        let size = ::mem::size_of_val(&(*set).fds_bits[0]) * 8;
+        (*set).fds_bits[fd / size] |= 1 << (fd % size);
+        return
+    }
+
+    pub fn FD_ZERO(set: *mut fd_set) -> () {
+        for slot in (*set).fds_bits.iter_mut() {
+            *slot = 0;
+        }
+    }
 }
 
 extern "C" {