Reworking bssl_crypto: make with_output_array_fallible use a bool.

This function took a `c_int` and checked that it was 1. But since
`initialized_struct_fallible` now expects a bool, this should too.

Change-Id: Ice7997c0847299f42fbc71fcc7b29acb66014bde
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/65547
Reviewed-by: Bob Beck <bbe@google.com>

rust/bssl-crypto/src/lib.rs

diff --git a/rust/bssl-crypto/src/lib.rs b/rust/bssl-crypto/src/lib.rs
index 21a2725..38096c3 100644
--- a/rust/bssl-crypto/src/lib.rs
+++ b/rust/bssl-crypto/src/lib.rs
@@ -311,7 +311,7 @@
 /// Safety: the closure must fully initialize the array if it returns one.
 unsafe fn with_output_array_fallible<const N: usize, F>(func: F) -> Option<[u8; N]>
 where
-    F: FnOnce(*mut u8, usize) -> core::ffi::c_int,
+    F: FnOnce(*mut u8, usize) -> bool,
 {
     let mut out_uninit = core::mem::MaybeUninit::<[u8; N]>::uninit();
     let out_ptr = if N != 0 {
@@ -319,7 +319,7 @@
     } else {
         core::ptr::null_mut()
     };
-    if func(out_ptr, N) == 1 {
+    if func(out_ptr, N) {
         // Safety: `func` promises to fill all of `out_uninit` if it returns one.
         unsafe { Some(out_uninit.assume_init()) }
     } else {

rust/bssl-crypto/src/x25519.rs

diff --git a/rust/bssl-crypto/src/x25519.rs b/rust/bssl-crypto/src/x25519.rs
index b91af54..26030b1 100644
--- a/rust/bssl-crypto/src/x25519.rs
+++ b/rust/bssl-crypto/src/x25519.rs
@@ -76,7 +76,7 @@
         // Safety: `X25519` indeed writes `SHARED_KEY_LEN` bytes.
         unsafe {
             with_output_array_fallible(|out, _| {
-                bssl_sys::X25519(out, self.0.as_ffi_ptr(), other_public_key.as_ffi_ptr())
+                bssl_sys::X25519(out, self.0.as_ffi_ptr(), other_public_key.as_ffi_ptr()) == 1
             })
         }
     }