CMake: enable dynamic-link library for libavrdude

[yegorich]

Add on option BUILD_SHARED_LIBS to also build a DLL variant
of the libavrdude library. Turn it off by default to preserve
current behavior.

[dl8dtl]

Speaking of that, I noticed that the static library built is named liblibavrdude.a.
There seems to be one "lib" too much. ;-)
Could we perhaps fix that at the same time?

[yegorich]

This could be a problem. CMake doesn't like the fact that two targets have the same name. I'd suggest to rename the library into, for example, either avrdudesdk or avrdudecore. But this is a matter of another PR.

[dl8dtl]

Strange behaviour of CMake. As they append the "lib" theirselves, they should also consider that a different target.

Actually, I just verified the FreeBSD port, we did ship libavrdude.a and libavrdude.so already in the past (with the automake system).

Googled a bit around,
SET_TARGET_PROPERTIES(libavrdude PROPERTIES PREFIX "")
should do the trick.

[yegorich]

It really does. Learned something new.

[dl8dtl]

It really does. Learned something new.

👍