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.

client/mysql.cc

@@ -3728,7 +3728,8 @@ com_edit(String *buffer,char *line __attribute__((unused)))
       !(editor = (char *)getenv("VISUAL")))
     editor = "vi";
   strxmov(buff,editor," ",filename,NullS);
-  (void) system(buff);
+  if(system(buff) == -1)
+    goto err;
 
   MY_STAT stat_arg;
   if (!my_stat(filename,&stat_arg,MYF(MY_WME)))