Merge pull request #11617 from swiftlang/lldb/libcxx-test-to-stable-21.x

🍒[lldb][test] Don't run libc++ API tests without a locally built libc++

Author: Michael137

lldb/packages/Python/lldbsuite/test/dotest.py

@@ -786,6 +786,10 @@ def canRunLibcxxTests():
         return True, "libc++ always present"
 
     if platform == "linux":
+        if not configuration.libcxx_include_dir or not configuration.libcxx_library_dir:
+            return False, "API tests require a locally built libc++."
+
+        # Make sure -stdlib=libc++ works since that's how the tests will be built.
         with tempfile.NamedTemporaryFile() as f:
             cmd = [configuration.compiler, "-xc++", "-stdlib=libc++", "-o", f.name, "-"]
             p = subprocess.Popen(