musl: powerpc(64): Decommonize termios definitions

PowerPC targets use their own, separate definitions of termios that
change the order of the c_line and c_cc fields.

See:
https://git.musl-libc.org/cgit/musl/tree/arch/powerpc/bits/termios.h#n3
https://git.musl-libc.org/cgit/musl/tree/arch/powerpc64/bits/termios.h#n3

Signed-off-by: Jens Reidel <adrian@travitia.xyz>

(backport <rust-lang#4518>)
(cherry picked from commit 0dfd754)

Author: Gelbpunkt

src/unix/linux_like/linux/musl/b32/powerpc.rs

@@ -4,6 +4,17 @@ use crate::prelude::*;
 pub type wchar_t = i32;
 
 s! {
+    pub struct termios {
+        pub c_iflag: crate::tcflag_t,
+        pub c_oflag: crate::tcflag_t,
+        pub c_cflag: crate::tcflag_t,
+        pub c_lflag: crate::tcflag_t,
+        pub c_cc: [crate::cc_t; crate::NCCS],
+        pub c_line: crate::cc_t,
+        pub __c_ispeed: crate::speed_t,
+        pub __c_ospeed: crate::speed_t,
+    }
+
     pub struct stat {
         pub st_dev: crate::dev_t,
         pub st_ino: crate::ino_t,

src/unix/linux_like/linux/musl/b64/powerpc64.rs

@@ -8,6 +8,17 @@ pub type nlink_t = u64;
 pub type blksize_t = c_long;
 
 s! {
+    pub struct termios {
+        pub c_iflag: crate::tcflag_t,
+        pub c_oflag: crate::tcflag_t,
+        pub c_cflag: crate::tcflag_t,
+        pub c_lflag: crate::tcflag_t,
+        pub c_cc: [crate::cc_t; crate::NCCS],
+        pub c_line: crate::cc_t,
+        pub __c_ispeed: crate::speed_t,
+        pub __c_ospeed: crate::speed_t,
+    }
+
     pub struct stat {
         pub st_dev: crate::dev_t,
         pub st_ino: crate::ino_t,

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

@@ -212,6 +212,8 @@ s! {
         __f_reserved: [c_int; 6],
     }
 
+    // PowerPC implementations are special, see the subfolders
+    #[cfg(not(any(target_arch = "powerpc", target_arch = "powerpc64")))]
     pub struct termios {
         pub c_iflag: crate::tcflag_t,
         pub c_oflag: crate::tcflag_t,