doc: recommend modern make for macOS depends

macOS ships with GNU Make 3.81 from 2006. This has caused
difficult to debug issues, see e.g.
9157d9e449.

Also add ninja, needed since qt6.

depends/README.md

@@ -18,6 +18,17 @@ To build dependencies for the current arch+OS:
 
     make
 
+### macOS
+
+Install Xcode Command Line Tools and Homebrew Package Manager,
+see [build-osx.md](../doc/build-osx.md).
+
+    brew install cmake make ninja
+
+To build dependencies for the current arch+OS:
+
+    gmake
+
 ### FreeBSD
 
     pkg install bash