Docs and build fixes to run Diffuse on macOS

Here we strip away Linux-only stuff so devs
can create a local "Mac build".

There might be other Linux-only stuff that
are not needed on Mac still. Follow-ups are
welcome.

data/meson.build

@@ -1,5 +1,6 @@
 pkgdatadir = join_paths(get_option('prefix'), get_option('datadir'), meson.project_name())
 
+if build_machine.system() == 'linux'
   desktop_file = i18n.merge_file(
     input: 'io.github.mightycreak.Diffuse.desktop.in',
     output: 'io.github.mightycreak.Diffuse.desktop',
@@ -30,6 +31,7 @@ if appstream_util.found()
       args: ['validate', appstream_file]
     )
   endif
+endif
 
 # Diffuse config file
 conf = configuration_data()

docs/developers/developers-setup.md

@@ -8,7 +8,7 @@ Diffuse depends on these projects:
 * PyPi
 * Cairo and GObject Introspection development headers
 * Meson
-* Flatpak and Flatpak builder
+* Flatpak and Flatpak builder (Linux only)
 
 ### Install the distribution dependencies
 
@@ -35,6 +35,20 @@ sudo dnf install python-pip cairo-devel cairo-gobject-devel meson flatpak flatpa
 _Note: Tested on Fedora 34_
 </details>
 
+<details>
+    <summary>Mac OS</summary>
+
+On Mac, all deps can be fetched using [Homebrew](https://docs.brew.sh/).
+
+```sh
+brew install meson python3 py3cairo pygobject3 gtk+3
+```
+
+_Note: Tested on macOS 12.5 (Monterey)_
+
+You don't need to use `pip` because the above `brew` command installs all dependencies.
+</details>
+
 ### Install the project dependencies
 
 To install the requirements just to execute the binary, run:
@@ -72,7 +86,7 @@ To uninstall Diffuse:
 flatpak remove io.github.mightycreak.Diffuse
 ```
 
-### Build, test and install using Meson
+## Build, test and install using Meson on Linux and Mac OS
 
 Diffuse build system is meson.
 

meson.build

@@ -10,4 +10,6 @@ subdir('data')
 subdir('src')
 subdir('po')
 
+if build_machine.system() == 'linux'
   meson.add_install_script('build-aux/meson/postinstall.py')
+endif