Replace arch-conditional c_char with a reexport

For any platforms that have `c_char` within a `cfg_if` block, ensure
they match the top-level `arch` definitions and reexport that to clean
up code.

src/hermit.rs

@@ -1,15 +1,8 @@
 //! Hermit C type definitions
 
+pub use crate::arch::c_char_def as c_char;
 use crate::prelude::*;
 
-cfg_if! {
-    if #[cfg(any(target_arch = "aarch64", target_arch = "riscv64"))] {
-        pub type c_char = u8;
-    } else {
-        pub type c_char = i8;
-    }
-}
-
 pub type c_schar = i8;
 pub type c_uchar = u8;
 pub type c_short = i16;

src/trusty.rs

@@ -1,18 +1,10 @@
+pub use crate::arch::c_char_def as c_char;
 use crate::prelude::*;
-
 pub type size_t = usize;
 pub type ssize_t = isize;
 
 pub type off_t = i64;
 
-cfg_if! {
-    if #[cfg(any(target_arch = "aarch64", target_arch = "arm"))] {
-        pub type c_char = u8;
-    } else if #[cfg(target_arch = "x86_64")] {
-        pub type c_char = i8;
-    }
-}
-
 pub type c_schar = i8;
 pub type c_uchar = u8;
 pub type c_short = i16;

src/unix/nuttx/mod.rs

@@ -1,21 +1,11 @@
+pub use crate::arch::c_char_def as c_char;
 use crate::prelude::*;
 use crate::{in6_addr, in_addr_t, timespec, DIR};
 
 pub type nlink_t = u16;
 pub type ino_t = u16;
 pub type blkcnt_t = u64;
 pub type blksize_t = i16;
-cfg_if! {
-    if #[cfg(any(
-        target_arch = "arm",
-        target_arch = "riscv32",
-        target_arch = "riscv64",
-    ))] {
-        pub type c_char = u8;
-    } else {
-        pub type c_char = i8;
-    }
-}
 pub type c_long = isize;
 pub type c_ulong = usize;
 pub type cc_t = u8;

src/unix/redox/mod.rs

@@ -1,12 +1,6 @@
+pub use crate::arch::c_char_def as c_char;
 use crate::prelude::*;
 
-cfg_if! {
-    if #[cfg(target_arch = "aarch64")] {
-        pub type c_char = u8;
-    } else {
-        pub type c_char = i8;
-    }
-}
 pub type wchar_t = i32;
 
 cfg_if! {

src/unix/solarish/mod.rs

@@ -1,14 +1,8 @@
 use core::mem::size_of;
 
+pub use crate::arch::c_char_def as c_char;
 use crate::prelude::*;
 
-cfg_if! {
-    if #[cfg(target_arch = "aarch64")] {
-        pub type c_char = u8;
-    } else {
-        pub type c_char = i8;
-    }
-}
 pub type c_long = i64;
 pub type c_ulong = u64;
 pub type caddr_t = *mut c_char;