* dbxread.c (dbx_symfile_init): Make size of the string table

	* dbxread.c (dbx_symfile_init):  Make size of the string table
	size field a define (DBX_STRINGTAB_SIZE_SIZE).  Ensure that the
	offset to the string table is nonzero and handle the nonexistant
	string table case, should it occur.  Ensure that the string table
	size read from the file is reasonable, with a minimum lower bound
	of DBX_STRINGTAB_SIZE_SIZE instead of zero.