bearssl-sys: use bindgen's usize setting

* `bindgen` can now set size_t as usize. This should remove the annoying
  type definition.

bearssl-sys/README.md

@@ -11,12 +11,6 @@ Currently BearSSL 0.6 and latest Rust stable is supported.
 * `bundled`: Build and link statically BearSSL. Needs a working C compiler and autoenables some sensible flags for the build target.
 * `dont-assume-size_t-equals-uintptr_t`: Use libc's `size_t` instead of `usize`. Should only needed when `sizeof(uintptr_t) != sizeof(size_t)`.
 
-## Misc.
-
-Once `core::ffi` types are stable, the bindings can and should be
-dependency-free for platforms where `dont-assume-size_t-equals-uintptr_t`
-isn't required.
-
 ## License
 
 This repository is licensed under the BSD-3-Clause. Please refer to `LICENSE` and

bearssl-sys/build/main.rs

@@ -5,6 +5,8 @@ use std::path::PathBuf;
 fn main() {
     linkage::configure();
 
+    let usize_equals_size_t = !cfg!(feature = "dont-assume-size_t-equals-uintptr_t");
+
     let bindings = bindgen::builder()
         .use_core()
         .ctypes_prefix("::core::ffi")
@@ -17,6 +19,7 @@ fn main() {
         .blocklist_type("__.*_t")
         .blocklist_type("size_t")
         .generate_comments(false)
+        .size_t_is_usize(usize_equals_size_t)
         .generate()
         .expect("Unable to generate bindings");
 

bearssl-sys/src/lib.rs

@@ -15,7 +15,4 @@
 #[cfg(feature = "dont-assume-size_t-equals-uintptr_t")]
 use libc::size_t;
 
-#[cfg(not(feature = "dont-assume-size_t-equals-uintptr_t"))]
-type size_t = usize;
-
 include!(concat!(env!("OUT_DIR"), "/bindings.rs"));