* [vcpkg] add missing implib definitions, fix shared lib extension on mac
(cherry picked from commit 2cddef9541)
* Better find_library suffixes and prefixes.
* moved additional suffix into a comment and reverted back to what is expected on windows
* updated documentation for add variables.
* Introduce an easier way to identify target systems...
* fix missing ()
* move the include around.
also added vcpkg_common_functions to be automatically included
* remove warning message
* added remaining VCPKG_CMAKE_SYSTEM_NAMEs found only in vcpkg_configure_cmake to load a toolchain.
* remove warning again from messed up merge