Updated macOS-specific documentation, especially regarding SIP issues

README.OSX

@@ -1,10 +1,17 @@
 README file for libfaketime on macOS
 ====================================
 
+!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+! If you compiled libfaketime successfully but even the simple examples   !
+! with the "date" command do not seem to work, please see the notes about !
+! SIP (system integrity protection) in this document!                     !
+!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+
 Support for macOS has meanwhile matured and many command line and
 GUI applications will run stable.
 
-Developments and tests are done on Mojave currently.
+Developments and tests are done on Catalina currently.
 
 Version 0.9.5 and higher no longer work with OSX <= 10.6 due to
 changes in the underlying system libraries. If you need libfaketime
@@ -138,6 +145,13 @@ However, there are two important aspects:
   application to a non-SIP-protected path, and if libfaketime still does not
   work, feel free to report it.
 
+  Please note that this also applies to simple programs such as /bin/date,
+  which is used as an example in the libfaketime documentation and help texts.
+
+  Again, either disable SIP on your system (which might not be the best idea),
+  or copy the applications / programs you want to use with libfaketime to
+  a different path, which is not SIP-protected, e.g., within your home directory.
+
 - We cannot and will not help with using libfaketime for proprietary or
   commercial software unless you are its developer trying to integrate
   libfaketime. Please contact the developers or the vendor directly if