Add emulator build instructions for MacOS

Author: jancona

compiling.md

@@ -183,7 +183,7 @@ To verify that radio_tool is in PATH, this should not return an error
 
 ## MacOS toolchain setup
 
-The MacOS toolchain setup is similar to that for Linux. Currently, neither the Linux emulator or the Zephyr-based tagets can be built on MacOS. The basic tools required to compile OpenRTX from the sources are _git_ and the _meson_ build system. To build the firmware for one of the radio targets, you'll require also the GCC toolchain for the miosix kernel. In this latter case, also _cmake_ and _libusb_ are required for compiling the external tools for flashing the radio.
+The MacOS toolchain setup is similar to that for Linux. Currently, the Zephyr-based tagets can't be built on MacOS. The basic tools required to compile OpenRTX from the sources are _git_ and the _meson_ build system. To build the firmware for one of the radio targets, you'll require also the GCC toolchain for the miosix kernel. In this latter case, also _cmake_ and _libusb_ are required for compiling the external tools for flashing the radio.
 
 #### Installing the basic tools
 
@@ -195,6 +195,17 @@ You will already have Git and the Xcode tools from the Homebrew installation pro
 brew install pkg-config meson
 ```
 
+#### Additional requirements only for the Emulator
+
+When compiling the Linux emulator version, the following additional packages are required:
+* SDL2 development package
+* Codec2 development package
+* `readline` package
+
+```
+brew install sdl2 codec2 readline
+```
+
 #### Tools required for firmware images
 
 To build the firmware images ready to be flashed on the radios, the miosix kernel GCC toolchain is required, as well as some additional tools used to encrypt and flash the binary files obtained at the end of the compilation process.
@@ -273,7 +284,7 @@ Where N is the number of cores that you want to allocate to the build process.
 
 ---
 
-## Compiling for Linux
+## Compiling the Emulator for Linux
 
 The software can be compiled with:
 
@@ -282,6 +293,13 @@ meson setup build_linux
 meson compile -C build_linux openrtx_linux
 ```
 
+## Compiling the Emulator for MacOS
+
+```
+MACOSX_DEPLOYMENT_TARGET=11 meson setup build_darwin
+MACOSX_DEPLOYMENT_TARGET=11 meson compile -C build_darwin openrtx_linux
+```
+
 **NOTE: if you are using a version of Meson older than v0.55.0, the above command will fail. To compile, use the following command:**
 
 ```
@@ -359,3 +377,7 @@ Once you have flashed MCUBOOT on your radio and obtained an OpenRTX image, you c
 ## Running on Linux
 
 To run OpenRTX on Linux you simply have to execute the binary `build_linux/openrtx_linux`, which was compiled with the instructions above.
+
+## Running on MacOS
+
+To run OpenRTX on MacOS you simply have to execute the binary `build_darwin/openrtx_linux`, which was compiled with the instructions above.