Prevent cmake from finding includes in miniconda.

[ktlim]

On Ubuntu, iconv should be used from the system/compiler library but cmake finds an (inconsistent) include file in miniconda. This change ensures that cmake will ignore all miniconda includes.

[timj]

Can we include the comment that we use in the MariaDB version of this?

# Prevent CMake from finding and linking against libraries distributed in $(dirname
# python)/../lib. This is CMake's default behaviour, but can cause us to erroneously link
# against libraries distributed by e.g. Anaconda.

[parejkoj]

Add @timj 's comment, otherwise this is good.