= GEOS RFC 6: Require explicit configure with  C++ API to use C++ API and ship c++ headers =

||RFC 6:  ||Drop support for C++ API and stop shipping the header||
||Author: ||Regina Obe        ||
||Contact:||lr@pcorp.us    ||
||Status: ||[https://lists.osgeo.org/pipermail/geos-devel/2017-October/thread.html#8050 In Discussion] ||

Past discussions 
[https://trac.osgeo.org/geos/ticket/553 Trac ticket to deprecate]
[https://lists.osgeo.org/pipermail/geos-devel/2017-January/007652.html another request to deprecate and osm2pgsql mess]
[https://lists.osgeo.org/pipermail/geos-devel/2012-June/005861.html more examples about how apps linking directly to GEOS C++ causing problems for other applications]
[https://lists.osgeo.org/pipermail/geos-devel/2017-January/007653.html Pointing out removing ability to use GEOS C++ reduces users freedoms]

This document proposes to change the ./configure to by default only allow use of the C-API.  The C++ API headers will only be installed if explicitly asked for
as detailed in https://lists.osgeo.org/pipermail/geos-devel/2017-October/008054.html

Any developers who want to use the C++ API will have to build with 

./configure --enable-c++-headers-install

As proposed in [https://lists.osgeo.org/pipermail/geos-devel/2017-October/008054.html]

I propose doing this in GEOS 3.7.0.

The main purpose is to discourage the use of the C++ API because we do not have the manpower to guarantee ABI compatiblity from version to version and thus using  in an environment where
the GEOS library is shared across many software is unsupported.

Currently osm2pgsql (and before Osmium) are the only ones that use the GEOS C++ API and largely distributed in s shared linux environment.