Merge pull request #1178 from isabelroses/fix/checks/homebrew

fix: allow users to disable the homebrew check

modules/system/checks.nix

@@ -297,7 +297,7 @@ let
   '';
 
   homebrewInstalled = ''
-    if [[ ! -f ${escapeShellArg config.homebrew.brewPrefix}/brew ]]; then
+    if [[ ! -f ${escapeShellArg config.homebrew.brewPrefix}/brew && -z "''${INSTALLING_HOMEBREW:-}" ]]; then
         echo "error: Using the homebrew module requires homebrew installed, aborting activation" >&2
         echo "Homebrew doesn't seem to be installed. Please install homebrew separately." >&2
         echo "You can install homebrew using the following command:" >&2