package/synergy: bump to version 1.8.5

package/synergy: bump to version 1.8.5

The project moved from SourceForge to GitHub.

The buildsystem changed from autotools to CMake.

Removed patches:
- 0001-includes.patch
    Not needed anymore, was fixed upstream.
- 0002-remove-werror.patch
    Autotools patch, no longer applicable.
- 0003-Fix-build-with-gcc-6.patch
    This patch was applied upstream:
    https://github.com/symless/synergy/commit/3d963bfbe7897d0a33ad477c06a6341c7708780d

Add patch to disable building of tests and allow building without gtest.

Signed-off-by: Pieterjan Camerlynck <pieterjan.camerlynck@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>