meson.build: don't use cp -p instead of --preserve-mode

The latter is not supported on OS X.

Author: Nikratio

test/meson.build

@@ -2,7 +2,7 @@ test_scripts = [ 'conftest.py', 'pytest.ini', 'test_sshfs.py',
                  'util.py' ]
 custom_target('test_scripts', input: test_scripts,
               output: test_scripts, build_by_default: true,
-              command: ['cp', '-fP', '--preserve=mode',
+              command: ['cp', '-fPp', 
                         '@INPUT@', meson.current_build_dir() ])
 
 # Provide something helpful when running 'ninja test'