Make BUILD_STATIC_PIC CMake option independent.
Make BUILD_STATIC_PIC CMake option independent.

Currently it was visible only if BUILD_STATIC was set, but it affects
both BUILD_STATIC and BUILD_PLUGINS_STATIC. And because
CMakeDependentOption doesn't support logic OR, I can't make it visible
if either of these two is set, so I'm just making it visible all the
time.

MiUishadow/magnum,DerThorsten/magnum,MiUishadow/magnum,MiUishadow/magnum,ashimidashajia/magnum,ashimidashajia/magnum,ashimidashajia/magnum,DerThorsten/magnum,ashimidashajia/magnum,MiUishadow/magnum,DerThorsten/magnum,DerThorsten/magnum,ashimidashajia/magnum,MiUishadow/magnum,MiUishadow/magnum,DerThorsten/magnum