error message corrected


include/my_base.h:
  EOVERFLOW moved to my_base.h - it is used not only in strtod.c
mysql-test/r/variables.result:
  error message corrected
mysql-test/t/variables.test:
  error message corrected
sql/item_func.cc:
  error message corrected
sql/sql_yacc.yy:
  error message corrected
strings/strtod.c:
  EOVERFLOW moved to my_base.h - it is used not only in strtod.c