readme: add additional information

Author: torque

build.zig.zon

@@ -13,6 +13,6 @@
         "build.zig.zon",
         "LICENSE",
         "LICENSE-LIBRESSL",
-        "README.md",
+        "readme.md",
     },
 }

readme.md

@@ -2,22 +2,42 @@
 
 This is [LibreSSL Portable](https://github.com/libressl/portable), packaged for [Zig](https://ziglang.org/).
 
-## Installation
+## Status
+
+This project currently builds the three main LibreSSL libraries as static libraries:
+
+- `libcrypto`: core cryptographic routines
+- `libssl`: OpenSSL 1.1 compatibility layer
+- `libtls`: LibreSSL's new cryptography API
+
+Operating systems and hardware architectures are supported on a best-effort basis. Building for Linux, macOS, and Windows (mingw64) is directly tested by CI.
+
+The command line programs `nc`, `ocspcheck`, and `openssl` are **not** currently built by this build system.
+
+## Usage
 
 First, update your `build.zig.zon`:
 
-```
+```sh
 # Initialize a `zig build` project if you haven't already
 zig init
-zig fetch --save <PLACEHOLDER>
+# replace <refname> with the version you want to use, e.g. 3.9.2
+zig fetch --save git+https://github.com/allyourcodebase/libressl#<refname>
 ```
 
-You can then import `libressl` in your `build.zig` with:
+You can then use `libressl` in your `build.zig` as follows:
 
 ```zig
 const libressl_dependency = b.dependency("libressl", .{
     .target = target,
     .optimize = optimize,
+    .@"enable-asm" = true, // enable assembly routines on supported platforms
 });
-your_exe.linkLibrary(libressl_dependency.artifact("tls"));
+your_exe.linkLibrary(libressl_dependency.artifact("tls")); // or "ssl", or "crypto"
 ```
+
+## Version Support Matrix
+
+|  Refname | LibreSSL Version | Zig `0.12.x` | Zig `0.13.x` | Zig `0.14.0-dev` |
+|----------|------------------|--------------|--------------|------------------|
+| `3.9.2`  | `3.9.2`          | ✅           | ✅          | ✅              |