Merge #986: [backport] Fix no_std MSRV

e45f6c7 bump version to 0.28.1 (Andrew Poelstra)
eaaa3d0 [backport] Fix `no_std` MSRV (mcroad)

Pull request description:

  Backport of #690 to 0.28

ACKs for top commit:
  tcharding:
    ACK e45f6c7

Tree-SHA512: 5e1459b83044acb2a628e612a45f5be5b05067429fcc7b4c4c46713bd61ee43032bbe52a80a2fc9a3ebe7cb649c2554c6500e7f7d6ea3da35e97150ca6431fc1

.gitignore

@@ -1,5 +1,6 @@
 target
 Cargo.lock
+dep_test
 
 #fuzz
 fuzz/hfuzz_target

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bitcoin"
-version = "0.28.0"
+version = "0.28.1"
 authors = ["Andrew Poelstra <apoelstra@wpsoftware.net>"]
 license = "CC0-1.0"
 homepage = "https://github.com/rust-bitcoin/rust-bitcoin/"

README.md

@@ -72,7 +72,8 @@ please join us in
 
 ## Minimum Supported Rust Version (MSRV)
 
-This library should always compile with any combination of features on **Rust 1.29**.
+This library should always compile with any combination of features (minus
+`no-std`) on **Rust 1.29** or **Rust 1.47** with `no-std`.
 
 Because some dependencies have broken the build in minor/patch releases, to
 compile with 1.29.0 you will need to run the following version-pinning command:

src/util/bip32.rs

@@ -74,7 +74,8 @@ impl fmt::Debug for ExtendedPrivKey {
             .field("parent_fingerprint", &self.parent_fingerprint)
             .field("child_number", &self.child_number)
             .field("chain_code", &self.chain_code)
-            .finish_non_exhaustive()
+            .field("private_key", &"[SecretKey]")
+            .finish()
     }
 }