fix(pthread): Fix cxx pthread example build for linux platform

Closes https://github.com/espressif/esp-idf/pull/14339

components/pthread/port/linux/pthread.c

@@ -0,0 +1,43 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+/*
+ * pthread port for Linux build
+ */
+
+#include "esp_pthread.h"
+#include <string.h>
+
+/**
+ * @brief Creates a default pthread configuration based
+ * on the values set via menuconfig.
+ *
+ * @return
+ *      A default configuration structure.
+ */
+esp_pthread_cfg_t esp_pthread_get_default_config(void)
+{
+    esp_pthread_cfg_t cfg = {
+        .stack_size = CONFIG_PTHREAD_TASK_STACK_SIZE_DEFAULT,
+        .prio = CONFIG_PTHREAD_TASK_PRIO_DEFAULT,
+        .inherit_cfg = false,
+        .thread_name = NULL,
+        .pin_to_core = 0,
+        .stack_alloc_caps = 0,
+    };
+
+    return cfg;
+}
+
+esp_err_t esp_pthread_set_cfg(const esp_pthread_cfg_t *cfg)
+{
+    return ESP_OK;
+}
+
+esp_err_t esp_pthread_get_cfg(esp_pthread_cfg_t *p)
+{
+    memset(p, 0, sizeof(*p));
+    return ESP_ERR_NOT_FOUND;
+}