README.md: document build and installation steps of macOS generic variant

Signed-off-by: Jan Noha <nohajc@gmail.com>

Author: nohajc

README.md

@@ -202,6 +202,29 @@ sudo make EFI=1 install
 
 ```
 
+### macOS (generic variant)
+
+#### Requirements
+
+* A working [Rust](https://www.rust-lang.org/) toolchain
+* A host running macOS 14 or newer
+* Homebrew packages `lld` and `xz`
+
+#### Compiling
+
+```
+make [FEATURE_OPTIONS]
+```
+
+The [init](init/init.c) binary is cross-compiled using clang and lld.
+A suitable sysroot is automatically generated by the Makefile from Debian repository.
+
+#### Installing
+
+```
+sudo make [FEATURE_OPTIONS] install
+```
+
 ## Using the library
 
 Despite being written in Rust, this library provides a simple C API defined in [include/libkrun.h](include/libkrun.h)