embed_crypto: use portable last_errno() for read() EINTR check

ober

e070df688524dd6f93599366fd7384c9ac713e09

diff --git a/jerboa-native-rs/src/embed_crypto.rs b/jerboa-native-rs/src/embed_crypto.rs
index 2752413..4487af4 100644
--- a/jerboa-native-rs/src/embed_crypto.rs
+++ b/jerboa-native-rs/src/embed_crypto.rs
@@ -227,7 +227,7 @@ pub extern "C" fn embed_read_passphrase(
             let mut c: u8 = 0;
             let n = read(fd, (&mut c) as *mut u8 as *mut c_void, 1);
             if n < 0 {
-                if *libc::__error() == EINTR { continue; }
+                if last_errno() == EINTR { continue; }
                 break;
             }
             if n <= 0 { break; }