CMake improvements

[vicroms]

Hi @ctabin

I propose some changes to the current CMake script.

• Remove the Win32 only restriction, as it is possible to build for Linux and Mac OS using CMake.
• Produce binaries with the same name for shared and static libraries (remove -shared and -static suffixes).
• Respect the BUILD_SHARED_LIBS variable to control whether to build static or shared.
• Support CMake integration via find_package(libzippp::libzippp) by producing libzipppConfig.cmake and libzipppTargets*.cmake files.
• Use a FindZIPLIB.cmake module to pull dependencies.
• Add option to disable building tests.

Tested with:

mkdir build
cd build
cmake -G "Visual Studio 16 2019" -A x64 .. 

From vcpkg PR #6801.

[ctabin]

@vicroms Thanks for your PR ! I'll test and merge asap. 😃

[ctabin]

@vicroms I'm trying to get CMake work on my linux with the following command:

make libraries
mkdir build
cd build
cmake -D LIBZIP_INCLUDE_DIR="../lib/libzip-1.5.2/lib ../lib/libzip-1.5.2/build" -D LIBZIP_LIBRARY=../lib/libzip-1.5.2/build/lib/ ..

However CMake doesn't like to have multiple paths in LIBZIP_INCLUDE_DIR (either separated with a space, comma, colon or semicolon).

If I set only one path, the cmake works fine, but I'm unable to execute make because some headers are missing. I would like to avoid some hack by coping manually all the headers in one directory because I'm pretty sure the solution is obvious 😅

Can I have you help here ? Thanks !

[ctabin]

Enquote ${LIBZIP_INCLUDE_DIRS} in cmake/FindLIBZIP.cmake