Reasons:
- Downloaded archives will have more meaningful names (e.g. capstone.zip
instead of 27c713fe4f6eaf9721785932d850b6291a6073fe.zip).
- This prevents collisions between projects (e.g. both yaracpp and yaramod are
in version 1.0.1 at the moment, so they were both downloaded as v1.0.1.zip).
From https://cmake.org/cmake/help/latest/variable/CMAKE_FIND_LIBRARY_PREFIXES.html:
This specifies what prefixes to add to library names when the
find_library() command looks for libraries.
What we want is CMAKE_STATIC_LIBRARY_PREFIX:
The prefix to use for the name of a static library, lib on UNIX.
Also, we are already using CMAKE_STATIC_LIBRARY_SUFFIX, so this change also
makes the used variables consistent.
The use of URL is safer than GIT_REPOSITORY as CMake does not update the cloned
repository when GIT_TAG changes. On the other hand, it downloads new sources
when URL changes.
