Manually fixup merge botches via direct comparison with NuttX r5447.

nuttx/include/cxx/cstdbool

@@ -46,4 +46,13 @@
 // Namespace
 //***************************************************************************
 
+//***************************************************************************
+// Namespace
+//***************************************************************************
+
+namespace std
+{
+  using ::_Bool8;
+}
+
 #endif // __INCLUDE_CXX_CSTDBOOL

nuttx/include/cxx/cstdio

@@ -52,6 +52,8 @@ namespace std
   using ::FILE;
   using ::fpos_t;
   using ::size_t;
+
+  using ::clearerr;
   using ::fclose;
   using ::fflush;
   using ::feof;
@@ -69,16 +71,24 @@ namespace std
   using ::ftell;
   using ::fwrite;
   using ::gets;
+  using ::ungetc;
+
   using ::printf;
   using ::puts;
   using ::rename;
   using ::sprintf;
+  using ::asprintf;
   using ::snprintf;
-  using ::ungetc;
+  using ::sscanf;
+  using ::perror;
+
   using ::vprintf;
   using ::vfprintf;
   using ::vsprintf;
+  using ::avsprintf;
   using ::vsnprintf;
+  using ::vsscanf;
+
   using ::fdopen;
   using ::statfs;
 }