adding a C function with optional arguments

i've poked about and made a new function "makecrypt(plainpass, salt)", and
it works ok.

basically, it is just a hook to the unix crypt() function.

i was wondering if someone could tell me how, if possible, to implement
a c function such that i can do:

> SELECT makecrypt('secret', 'salt');
or
> SELECT makecrypt('secret');

such that if salt is not specified, the c function would make one up.

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[ Jim Mercer          jim@pneumonoultramicroscopicsilicovolcanoconiosis.ca ]
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