improve installation docs

README.md

@@ -3,9 +3,37 @@
 Uses [PHPER framework](https://github.com/phper-framework/phper) and [notify-rs](https://github.com/notify-rs/notify) 
 to build the extension. Supports PHP 8.1, 8.2 and 8.3 for Linux and macOS.
 
-## Installation
+## Build from source
 
-In the release download the .so (Linux) or .dylib (macOS) file for your PHP version. Lookup the value of your
+```shell
+# For Debian/Ubuntu
+sudo apt install gcc make llvm-13-dev libclang-13-dev protobuf-c-compiler protobuf-compiler
+
+# For Alpine Linux
+apk add gcc make musl-dev llvm15-dev clang15-dev protobuf-c-compiler
+
+# For MacOS
+brew install llvm@13
+export LIBCLANG_PATH=$(brew --prefix llvm@13)/lib
+
+# recommended rust setup, see https://www.rust-lang.org/tools/install
+curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
+
+# build using cargo
+cargo build --release
+
+# move .so (Linux) or .so (MacOS) file to your extension dir
+PHP_EXTENSION_DIR=`php -r "echo ini_get('extension_dir');"`
+mv target/release/libphp_ext_fs_notify.so ${PHP_EXTENSION_DIR}/fs_notify.so
+mv target/release/libphp_ext_fs_notify.dylib ${PHP_EXTENSION_DIR}/fs_notify.dylib
+
+# enable the extension but putting in the ini file
+echo 'extension=fs_notify.so' | tee -a /etc/php/${PHP_VERSION}/cli/conf.d/20-fs_notify.ini > /dev/null
+```
+
+## Install pre-created .so and .dylib
+
+In the release download the .so (Ubuntu) or .dylib (macOS) file for your PHP version. Lookup the value of your
 exension_dir, move the extension into that directory. Enable the extension by putting an ini-file in the conf.d folder 
 of your php version. It might look as follows.