bpo-11191: skip unsupported test_distutils case for AIX with xlc (GH-8709)

Command line options for the xlc compiler behave differently from gcc and clang,
so skip this test case for now when xlc is the compiler.

Patch by aixtools (Michael Felt)

command/config.py

@@ -328,7 +328,6 @@ class config(Command):
         return self.try_cpp(body="/* No body */", headers=[header],
                             include_dirs=include_dirs)
 
-
 def dump_file(filename, head=None):
     """Dumps a file content into log.info.
 

tests/test_config_cmd.py

@@ -39,11 +39,17 @@ class ConfigTestCase(support.LoggingSilencer,
 
     @unittest.skipIf(sys.platform == 'win32', "can't test on Windows")
     def test_search_cpp(self):
+        import shutil
         cmd = missing_compiler_executable(['preprocessor'])
         if cmd is not None:
             self.skipTest('The %r command is not found' % cmd)
         pkg_dir, dist = self.create_dist()
         cmd = config(dist)
+        cmd._check_compiler()
+        compiler = cmd.compiler
+        is_xlc = shutil.which(compiler.preprocessor[0]).startswith("/usr/vac")
+        if is_xlc:
+            self.skipTest('xlc: The -E option overrides the -P, -o, and -qsyntaxonly options')
 
         # simple pattern searches
         match = cmd.search_cpp(pattern='xxx', body='/* xxx */')