Fix a CMake link issue when using shared libs

MaestroConfig.cmake.in

@@ -32,4 +32,8 @@
 set(PREFIX @prefix@)
 
 set(Maestro_INCLUDE_DIRS ${PREFIX}/include/maestro)
+if (BUILD_SHARED_LIBRARIES)
+  set(Maestro_LIBRARIES ${PREFIX}/lib/libmaestro.so)
+else()
   set(Maestro_LIBRARIES ${PREFIX}/lib/libmaestro.a)
+endif()