Re-export core::ffi integer types rather than redefining

Since the MSRV was raised to 1.65, we can use these aliases directly
rather than copying them. In a future version, we can consider
deprecation.

Author: tgross35

src/primitives.rs

@@ -6,64 +6,6 @@
 //!
 //! The fixed-width integer aliases are deprecated: use the Rust types instead.
 
-pub type c_schar = i8;
-pub type c_uchar = u8;
-pub type c_short = i16;
-pub type c_ushort = u16;
-
-pub type c_longlong = i64;
-pub type c_ulonglong = u64;
-
-pub type c_float = f32;
-pub type c_double = f64;
-
-cfg_if! {
-    if #[cfg(all(
-        not(windows),
-        not(target_vendor = "apple"),
-        not(target_os = "vita"),
-        any(
-            target_arch = "aarch64",
-            target_arch = "arm",
-            target_arch = "csky",
-            target_arch = "hexagon",
-            target_arch = "msp430",
-            target_arch = "powerpc",
-            target_arch = "powerpc64",
-            target_arch = "riscv32",
-            target_arch = "riscv64",
-            target_arch = "s390x",
-            target_arch = "xtensa",
-        )
-    ))] {
-        pub type c_char = u8;
-    } else {
-        // On every other target, c_char is signed.
-        pub type c_char = i8;
-    }
-}
-
-cfg_if! {
-    if #[cfg(any(target_arch = "avr", target_arch = "msp430"))] {
-        pub type c_int = i16;
-        pub type c_uint = u16;
-    } else {
-        pub type c_int = i32;
-        pub type c_uint = u32;
-    }
-}
-
-cfg_if! {
-    if #[cfg(all(target_pointer_width = "64", not(windows)))] {
-        pub type c_long = i64;
-        pub type c_ulong = u64;
-    } else {
-        // The minimal size of `long` in the C standard is 32 bits
-        pub type c_long = i32;
-        pub type c_ulong = u32;
-    }
-}
-
 #[deprecated(since = "0.2.55", note = "Use i8 instead.")]
 pub type int8_t = i8;
 #[deprecated(since = "0.2.55", note = "Use i16 instead.")]
@@ -81,6 +23,23 @@ pub type uint32_t = u32;
 #[deprecated(since = "0.2.55", note = "Use u64 instead.")]
 pub type uint64_t = u64;
 
+// FIXME(1.0): Deprecate these aliases in a few releases, remove in 1.0.
+pub use core::ffi::{
+    c_char,
+    c_double,
+    c_float,
+    c_int,
+    c_long,
+    c_longlong,
+    c_schar,
+    c_short,
+    c_uchar,
+    c_uint,
+    c_ulong,
+    c_ulonglong,
+    c_ushort,
+};
+
 cfg_if! {
     if #[cfg(all(
         target_arch = "aarch64",