Bump LLVM commit to 687bd77e2c26487cba727aacfa7067dd01286be0

Skips through the followings commits that do not affect the Rust port:
* 8e58b79f67a9f921733b105a874c0d4f69dd50da: fixes typos not present in the Rust port
* 687bd77e2c26487cba727aacfa7067dd01286be0: C++ specific changes

Author: eduardosm

Cargo.toml

@@ -2,7 +2,7 @@
 members = ["fuzz"]
 
 [workspace.package]
-version = "0.2.1+llvm-69668590592f"
+version = "0.2.1+llvm-687bd77e2c26"
 edition = "2021"
 license = "Apache-2.0 WITH LLVM-exception"
 

src/lib.rs

@@ -1,6 +1,6 @@
 //! Port of LLVM's APFloat software floating-point implementation from the
 //! following C++ sources (please update commit hash when backporting):
-//! <https://github.com/llvm/llvm-project/commit/69668590592fcca2c2b22ba2257be57f0319fc9c>
+//! <https://github.com/llvm/llvm-project/commit/687bd77e2c26487cba727aacfa7067dd01286be0>
 //! * `llvm/include/llvm/ADT/APFloat.h` -> `Float` and `FloatConvert` traits
 //! * `llvm/lib/Support/APFloat.cpp` -> `ieee` and `ppc` modules
 //! * `llvm/unittests/ADT/APFloatTest.cpp` -> `tests` directory