warn about multiple mysqld --user parameters only if their arguments differ

scripts/mysqld_safe.sh:
  don't protect mysqld from multiple --user commands - mysqld can take care of itself
sql/mysqld.cc:
  warn about multiple --user parameters only if their arguments differ

scripts/mysqld_safe.sh

@@ -43,13 +43,7 @@ parse_arguments() {
       --basedir=*) MY_BASEDIR_VERSION=`echo "$arg" | sed -e "s;--basedir=;;"` ;;
       --datadir=*) DATADIR=`echo "$arg" | sed -e "s;--datadir=;;"` ;;
       --pid-file=*) pid_file=`echo "$arg" | sed -e "s;--pid-file=;;"` ;;
-      --user=*)
-        if test $SET_USER -eq 0
-        then
-          user=`echo "$arg" | sed -e "s;--[^=]*=;;"`
-        fi
-        SET_USER=1
-        ;;
+      --user=*) user=`echo "$arg" | sed -e "s;--[^=]*=;;"` ; SET_USER=1 ;;
 
       # these two might have been set in a [mysqld_safe] section of my.cnf
       # they are added to mysqld command line to override settings from my.cnf

sql/mysqld.cc

@@ -4624,7 +4624,7 @@ get_one_option(int optid, const struct my_option *opt __attribute__((unused)),
     mysql_data_home= mysql_real_data_home;
     break;
   case 'u':
-    if (!mysqld_user)
+    if (!mysqld_user || !strcmp(mysqld_user, argument))
       mysqld_user= argument;
     else
       fprintf(stderr, "Warning: Ignoring user change to '%s' because the user was set to '%s' earlier on the command line\n", argument, mysqld_user);