build: Force default libdir location on Windows
When libdir is different from default directory, meson install import library (
libhandy-0.0.dll; MinGW, instead, wants import libraries in
libdir and libraries in
So we need defaults libdir on MinGW build.
install_dir arg from
[true] in libhandy
shared_library call set installation in default directory, so it fixes the problem.
I have not changed the global variable
[true] on Windows because this breaks the other targets depending on
CI failing should not depend on this because the change should not affect linux/unix. Also, it builds on my machine.