Add SO_INCOMING_CPU for targets arm-unknown-linux-*

- fixes rust-lang/socket2#213

Author: zonyitoo

src/unix/linux_like/linux/gnu/b32/arm/mod.rs

@@ -325,6 +325,7 @@ pub const SO_PEERSEC: ::c_int = 31;
 pub const SO_SNDBUFFORCE: ::c_int = 32;
 pub const SO_RCVBUFFORCE: ::c_int = 33;
 pub const SO_PASSSEC: ::c_int = 34;
+pub const SO_INCOMING_CPU: ::c_int = 49;
 
 pub const SA_SIGINFO: ::c_int = 0x00000004;
 pub const SA_NOCLDWAIT: ::c_int = 0x00000002;

src/unix/linux_like/linux/musl/b32/arm/mod.rs

@@ -383,6 +383,7 @@ pub const SO_RCVBUFFORCE: ::c_int = 33;
 pub const SO_PASSSEC: ::c_int = 34;
 pub const SO_PROTOCOL: ::c_int = 38;
 pub const SO_DOMAIN: ::c_int = 39;
+pub const SO_INCOMING_CPU: ::c_int = 49;
 
 pub const SA_ONSTACK: ::c_int = 0x08000000;
 pub const SA_SIGINFO: ::c_int = 0x00000004;