[geos] Upgrade to GEOS 3.6.4

[mwtoews]

Update port/geos to version 3.6.4, released 2019-10-04

See details in this release announcement

Note that this is not the current version, as I'd like to re-create each major version, so you can expect me to also create pull requests for GEOS versions 3.7.3 and 3.8.1 (current).

---

• What does your PR fix? None.
• Which triplets are supported/not supported? Have you updated the CI baseline? Not sure, and nope.
• Does your PR follow the maintainer guide? Yes.

[msftclas]

All CLA requirements met.

[strega-nil]

This looks great! Just needs a slight change. Thanks so much :)

[dan-shaw]

/azp run

[dan-shaw]

/azp run

[dan-shaw]

@mwtoews @LilyWangL This is failing the CI for osg-qt. Do you know if this is a related error or an error with our CI?

[LilyWangL]

@mwtoews @LilyWangL This is failing the CI for osg-qt. Do you know if this is a related error or an error with our CI?

Port osg-qt build failed is not a related error with this PR.

[LilyWangL]

/azp run

[mwtoews]

is this ready to merge yet?

[LilyWangL]

@ras0219-msft This PR is ready to merge.

[ras0219-msft]

LGTM, thanks for this PR!

[jjpepper]

Is GOES meant to be working? How is it meant to be used from CMake?

See example from their project: https://git.osgeo.org/gitea/geos/geos/src/branch/master/examples/client/CMakeLists.txt This doesn't work with vcpkg (even when the version number is removed). It would be great if Vcpkg could tell the user when a package is installed if special instructions are needed for linking etc.