build: Fix 'make deploy' for OSX

Native OSX uses system tools rather than 3rd party dependencies. rsvg-convert
is still required, though.

contrib/macdeploy/macdeployqtplus

@@ -791,7 +791,7 @@ if config.dmg is not None:
         except subprocess.CalledProcessError as e:
             sys.exit(e.returncode)
         
-        m = re.search("/Volumes/(.+$)", output)
+        m = re.search("/Volumes/(.+$)", output.decode())
         disk_root = m.group(0)
         disk_name = m.group(1)
         
@@ -868,7 +868,7 @@ if config.dmg is not None:
             print(s)
 
         p = subprocess.Popen(['osascript', '-'], stdin=subprocess.PIPE)
-        p.communicate(input=s)
+        p.communicate(input=s.encode('utf-8'))
         if p.returncode:
             print("Error running osascript.")