The iconv module converts text between character sets inside nginx, using
the iconv(3) facility of the system.  It brings three directives:
set_iconv converts the content of one variable into another, iconv_filter
converts a response body as it is sent, and iconv_buffer_size sizes the
buffers the filter works with.

This port only installs the module sources.  The module itself is built by
the nginx ports when their ICONV option is enabled.