join(1) reject -a option's argument with space

[Takehiko NOZAKI]

join(1) reject space character between -a option and its argument.

without space work file.

$ join -a1 -a2 ...

but with space may fail with showing usage.

$ join -a 1 -a 2 ...
usage: join [-a fileno | -v fileno] [-e string] [-j fileno field]
            [-o list] [-t char] [-1 field] [-2 field] file1 file2

[Takehiko NOZAKI]

according to manpage, it is intentional and effort for keeping backword compatibility. FreeBSD/OpenBSD kill this silly anachronism 11years before. how slower NetBSD's time!