Modernize CMake and switch to CMake 3.15

[mrexodia]

Closes #1826

Some context

This refactors capstone's CMake to be compatible with both find_package and FetchContent. You can build capstone like this:

cmake -B build -DBUILD_SHARED_LIBS=OFF # or whatever options you want
cmake --build build
cmake --install build --prefix build/install

Then in your project's CMakeLists.txt:

find_package(capstone REQUIRED)

add_executable(my_tool src/main.cpp)
target_link_libraries(my_tool PRIVATE capstone::capstone)

And to build you point CMAKE_PREFIX_PATH to the build/install you just created:

cmake -B build -DCMAKE_PREFIX_PATH=/path/to/capstone/build/install

Or alternatively you can use FetchContent:

include(FetchContent)

message(STATUS "Fetching capstone (cmake-packaging)...")
FetchContent_Declare(
	capstone
	GIT_REPOSITORY
		https://github.com/LLVMParty/capstone
	GIT_TAG
		cmake-packaging
)
FetchContent_MakeAvailable(capstone) 

add_executable(my_tool src/main.cpp)
target_link_libraries(my_tool PRIVATE capstone::capstone)

This seems to be the "intended" way to use CMake and it should make it easier for other tools (like Triton) to link capstone in a way consistent with other packages. It should also be compatible with vcpkg/Hunter without any custom work.

Stuff left

• Fuzzing is failing (no idea why, it seems to clone the wrong branch)
• Fix python distribution

[kabeor]

Very cool! Merged.