build: produce a .zip for macOS distribution

Instead of a .dmg.

Co-authored-by: fanquake <fanquake@gmail.com>

depends/README.md

@@ -48,7 +48,7 @@ The paths are automatically configured and no other options are needed unless ta
 
 #### For macOS cross compilation
 
-    sudo apt-get install curl bsdmainutils cmake libz-dev python3-setuptools xorriso
+    sudo apt-get install curl bsdmainutils cmake libz-dev python3-setuptools xorriso zip
 
 Note: You must obtain the macOS SDK before proceeding with a cross-compile.
 Under the depends directory, create a subdirectory named `SDKs`.