Fix compiler warnings

sql/mysqld.cc:
  Fix compiler warning
sql/stacktrace.c:
  Fix compiler warning

sql/mysqld.cc

@@ -599,7 +599,9 @@ pthread_mutex_t  LOCK_server_started;
 pthread_cond_t  COND_server_started;
 
 int mysqld_server_started= 0;
+#ifndef EMBEDDED_LIBRARY
 static uint thr_kill_signal;
+#endif
 
 File_parser_dummy_hook file_parser_dummy_hook;
 

sql/stacktrace.c

@@ -53,8 +53,6 @@ void safe_print_str(const char* name, const char* val, int max_len)
 #define SIGRETURN_FRAME_OFFSET 23
 #endif
 
-static my_bool is_nptl;
-
 #if defined(__alpha__) && defined(__GNUC__)
 /*
   The only way to backtrace without a symbol table on alpha