Add target-cpu RUSTFLAGS for SIMD performance

Related: #5

Author: esensar

.github/workflows/build.yml

@@ -2,6 +2,9 @@ name: Build binaries
 
 on: workflow_dispatch
 
+env:
+  RUSTFLAGS: "-C target-cpu=x86-64-v3"
+
 jobs:
   build:
     name: Build

README.md

@@ -104,6 +104,8 @@ $ make
 # make install
 ```
 
+For maximum efficiency, use `RUSTFLAGS="-C target-cpu=native"` when running make, if portability is not an issue.
+
 ## License
 Stringsimile - tool for comparing target strings from JSON-structured streams against a large set of other strings using rules such as Levenshtein, Jaro, Soundex, IDN Confusables and more.
 Copyright (C) 2025 Quad9 DNS