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

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

tools/test_apps/linux_compatible/generic_build_test/main/CMakeLists.txt

@@ -1,2 +1,3 @@
 idf_component_register(SRCS "generic_build_test.c"
-                    INCLUDE_DIRS ".")
+                    INCLUDE_DIRS "."
+                    PRIV_REQUIRES pthread)

tools/test_apps/linux_compatible/generic_build_test/main/generic_build_test.c

@@ -8,8 +8,13 @@
 #include <stddef.h>
 #include "inttypes_ext.h"
 
+#include "esp_pthread.h"
+
 void app_main(void)
 {
     size_t size = 47;
     printf("size is: %" PRIuSIZE "\n", size); // test IDF's PRIuSIZE
+
+    esp_pthread_cfg_t pthread_config = esp_pthread_get_default_config();
+    (void)pthread_config;
 }