SetupPsychtoolbox(): Try to fix it properly for macOS wrt. xattr.

Skip xattr calls for .mltbx installed files via Matlab Add-On explorer, as those already
have their quarantine flags removed.

For other (zip file) install locations, handle blanks/spaces in the installation path.

Also some output text cleanups and fixes. Tested with .mltbx and zip file path install on
path with spaces etc. Lets hope this goes better.

Psychtoolbox/SetupPsychtoolbox.m

@@ -21,7 +21,7 @@ function SetupPsychtoolbox(tryNonInteractiveSetup)
 % folder. Obviously you need to somehow get a copy, either via conventional
 % download from a computer with network connection, visit this URL for that
 % download: http://psychtoolbox.org/download.html
-% Or from a helpful colleague or copied from some other machine.
+% Or from a helpful colleague, or copied from some other machine.
 %
 % 2. Change your Matlab/Octave working directory to the Psychtoolbox installation
 % folder, e.g., 'cd /Applications/Psychtoolbox'.
@@ -55,6 +55,8 @@ function SetupPsychtoolbox(tryNonInteractiveSetup)
 % 04/01/16 mk  64-Bit Octave-4 support for MS-Windows established.
 % 06/01/16 mk  32-Bit Octave-4 support for MS-Windows removed.
 % 01/25/24 mk  Cleanup, dead code removal.
+% 06/12/24 mk  Fixup for spaces in install path on macOS for use of xattr,
+%              and skip xattr if installed as .mltbx file via Add-On explorer.
 
 % Flush all MEX files: This is needed at least on M$-Windows if Screen et al. are still loaded.
 clear mex; %#ok<CLMEX>
@@ -75,7 +77,7 @@ function SetupPsychtoolbox(tryNonInteractiveSetup)
 
 if ~IsWin && ~IsOSX && ~IsLinux
     fprintf('Sorry, this updater doesn''t support your operating system: %s.\n', computer);
-    fprintf([mfilename ' can only install the Linux, Windows and macOS versions of the Psychtoolbox-3.\n']);
+    fprintf([mfilename ' can only set up the Linux, Windows and macOS versions of the Psychtoolbox-3.\n']);
     error(['Your operating system is not supported by ' mfilename '.']);
 end
 
@@ -106,7 +108,7 @@ function SetupPsychtoolbox(tryNonInteractiveSetup)
 
     fprintf(['Once "savepath" works (no error message), run ' mfilename ' again.\n']);
     fprintf('Alternatively you can choose to continue with installation, but then you will have\n');
-    fprintf('to resolve this permission isssue later and add the path to the Psychtoolbox manually.\n\n');
+    fprintf('to resolve this permission issue later and add the path to the Psychtoolbox manually.\n\n');
     if ~tryNonInteractiveSetup
         answer=input('Do you want to continue the installation despite the failure of SAVEPATH (yes or no)? ','s');
     else
@@ -196,7 +198,8 @@ function SetupPsychtoolbox(tryNonInteractiveSetup)
     fprintf('Success.\n\n');
 end
 
-if IsOSX
+% macOS and not a Matlab add-on? Add-on toolboxes don't need quarantine removal.
+if IsOSX && isempty(strfind(targetdirectory, 'MATLAB Add-Ons')) %#ok<STREMP>
     % Apples trainwreck needs special treatment. If Psychtoolbox has been
     % downloaded via a webbrowser as a zip file or tgz file and then
     % extracted, then all binary executable files like .dylib's and
@@ -205,6 +208,10 @@ function SetupPsychtoolbox(tryNonInteractiveSetup)
     % Thanks Apple! Use the xattr command to remove the quarantine flag.
     fprintf('Trying to fixup Apple macOS broken security workflow by removing the quarantine flag from our mex files...\n\n');
 
+    % Escape all spaces in the path p with a backslash, so shell utilities
+    % like xattr can work and don't choke on pathes with blanks:
+    p = strrep(p, ' ', '\ ');
+
     if IsOctave
         % Fix the Octave mex files:
         if IsARM
@@ -231,7 +238,7 @@ function SetupPsychtoolbox(tryNonInteractiveSetup)
         if isempty(strfind(msg, 'xattr: com.apple.quarantine')) %#ok<STREMP>
             fprintf('FAILED! Psychtoolbox will likely not work correctly!\n');
             PsychPaidSupportAndServices(2);
-            error(['Removing the quarantine flag from our mex files to workaround macOS brokeness failed! Error was: ' msg]);
+            warning(['Removing the quarantine flag from our mex files to workaround macOS brokeness failed! Error was: ' msg]);
         end
     end
 end