Bug#37995 Error message truncation in test "innodb" in embedded mode.

code backported from 6.0


per-file messages:
  include/my_global.h
    Remove SC_MAXWIDTH. This is unused and irrelevant nowadays.
  include/my_sys.h
    Remove errbuf declaration and unused definitions.
  mysys/my_error.c
    Remove errbuf definition and move and adjust ERRMSGSIZE.
  mysys/my_init.c
    Declare buffer on the stack and use my_snprintf.
  mysys/safemalloc.c
    Use size explicitly. It's more than enough for the message at hand.
  sql/sql_error.cc
    Use size explicitly. It's more than enough for the message at hand.
  sql/sql_parse.cc
    Declare buffer on the stack. Use my_snprintf as it will result in
    less stack space being used than by a system provided sprintf --
    this allows us to put the buffer on the stack without causing much
    trouble. Also, the use of errbuff here was not thread-safe as the
    function can be entered concurrently from multiple threads.
  sql/sql_table.cc
    Use MYSQL_ERRMSG_SIZE. Extra space is not needed as my_snprintf will
    nul terminate strings.
  storage/myisam/ha_myisam.cc
Use MYSQL_ERRMSG_SIZE.
  sql/share/errmsg.txt
    Error message truncation in test "innodb" in embedded mode
    filename in the error message can safely take up to 210 symbols.

mysys/safemalloc.c

@@ -147,7 +147,7 @@ void *_mymalloc(size_t size, const char *filename, uint lineno, myf MyFlags)
       error_handler_hook=fatal_error_handler_hook;
     if (MyFlags & (MY_FAE+MY_WME))
     {
-      char buff[SC_MAXWIDTH];
+      char buff[256];
       my_errno=errno;
       sprintf(buff,"Out of memory at line %d, '%s'", lineno, filename);
       my_message(EE_OUTOFMEMORY, buff, MYF(ME_BELL+ME_WAITTANG+ME_NOREFRESH));