C compiler error when using PostGres

I recently upgraded the hardrive on our database system and copied all
of the Postgres files from the old harddrive to the new one.

Everything seems to work find except when I try to compile a C program
that uses SQL backend commands. The program did compile on the old
harddrive and ran fine. Now, during compilation I get the following
error:

/database/local/pgsql/lib/libpq.a(fe-auth.o): In function
`pg_password_sendauth':
fe-auth.o(.text+0x17): undefined reference to `crypt'

Anyone know how to fix this?

Thanks.
-Tony

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