[lldb] Only use PyConfig when LLDB_EMBED_PYTHON_HOME is enabled (llvm#152588)

PyConfig and friends are not part of the stable API. We could switch
back to Py_SetPythonHome, which has been deprecated, but still part of
the stable API. For now, limit the use of PyConfig to when
LLDB_EMBED_PYTHON_HOME is enabled, which essentially means Windows.
Changing the order doesn't seem to matter.

Author: JDevlieghere

lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp

@@ -92,25 +92,6 @@ namespace {
 struct InitializePythonRAII {
 public:
   InitializePythonRAII() {
-    PyConfig config;
-    PyConfig_InitPythonConfig(&config);
-
-#if LLDB_EMBED_PYTHON_HOME
-    static std::string g_python_home = []() -> std::string {
-      if (llvm::sys::path::is_absolute(LLDB_PYTHON_HOME))
-        return LLDB_PYTHON_HOME;
-
-      FileSpec spec = HostInfo::GetShlibDir();
-      if (!spec)
-        return {};
-      spec.AppendPathComponent(LLDB_PYTHON_HOME);
-      return spec.GetPath();
-    }();
-    if (!g_python_home.empty()) {
-      PyConfig_SetBytesString(&config, &config.home, g_python_home.c_str());
-    }
-#endif
-
     // The table of built-in modules can only be extended before Python is
     // initialized.
     if (!Py_IsInitialized()) {
@@ -134,9 +115,30 @@ struct InitializePythonRAII {
       PyImport_AppendInittab("_lldb", LLDBSwigPyInit);
     }
 
+#if LLDB_EMBED_PYTHON_HOME
+    PyConfig config;
+    PyConfig_InitPythonConfig(&config);
+
+    static std::string g_python_home = []() -> std::string {
+      if (llvm::sys::path::is_absolute(LLDB_PYTHON_HOME))
+        return LLDB_PYTHON_HOME;
+
+      FileSpec spec = HostInfo::GetShlibDir();
+      if (!spec)
+        return {};
+      spec.AppendPathComponent(LLDB_PYTHON_HOME);
+      return spec.GetPath();
+    }();
+    if (!g_python_home.empty()) {
+      PyConfig_SetBytesString(&config, &config.home, g_python_home.c_str());
+    }
+
     config.install_signal_handlers = 0;
     Py_InitializeFromConfig(&config);
     PyConfig_Clear(&config);
+#else
+    Py_InitializeEx(/*install_sigs=*/0);
+#endif
 
     // The only case we should go further and acquire the GIL: it is unlocked.
     PyGILState_STATE gil_state = PyGILState_Ensure();