Bug #43414 Parenthesis (and other) warnings compiling MySQL

with gcc 4.3.2
      
This patch fixes a number of GCC warnings about variables used
before initialized. A new macro UNINIT_VAR() is introduced for
use in the variable declaration, and LINT_INIT() usage will be
gradually deprecated. (A workaround is used for g++, pending a
patch for a g++ bug.)
      
GCC warnings for unused results (attribute warn_unused_result)
for a number of system calls (present at least in later
Ubuntus, where the usual void cast trick doesn't work) are
also fixed.


client/mysqlmanager-pwgen.c:
  A fix for warn_unused_result, adding fallback to use of
  srand()/rand() if /dev/random cannot be used. Also actually
  adds calls to rand() in the second branch so that it actually
  creates a random password.

sql/sql_base.cc

@@ -706,7 +706,7 @@ void close_temporary_tables(THD *thd)
     return;
   }
 
-  TABLE *next,
+  TABLE *UNINIT_VAR(next),
     *prev_table /* prev link is not maintained in TABLE's double-linked list */;
   bool was_quote_show= true; /* to assume thd->options has OPTION_QUOTE_SHOW_CREATE */
   // Better add "if exists", in case a RESET MASTER has been done
@@ -716,7 +716,6 @@ void close_temporary_tables(THD *thd)
   memcpy(buf, stub, stub_len);
   String s_query= String(buf, sizeof(buf), system_charset_info);
   bool found_user_tables= false;
-  LINT_INIT(next);
 
   /*
      insertion sort of temp tables by pseudo_thread_id to build ordered list
@@ -4142,8 +4141,7 @@ find_item_in_list(Item *find, List<Item> &items, uint *counter,
     (and not an item that happens to have a name).
   */
   bool is_ref_by_name= 0;
-  uint unaliased_counter;
-  LINT_INIT(unaliased_counter);                 // Dependent on found_unaliased
+  uint UNINIT_VAR(unaliased_counter);           // Dependent on found_unaliased
 
   *resolution= NOT_RESOLVED;