build(cmake): Make monolithic libs be built inside Velox's own binary directory when being used as a subproject (#12144)

Summary:
Similar to #12128, currently when Velox is imported as a subproject of another project, the monolithic libs `libvelox.a` / `libvelox.so` will be generated in root project's binary directory which is sub-optimal.

The patch fixes the issue so the libs will be generated inside Velox's binary directory.

Pull Request resolved: #12144

Reviewed By: kgpai

Differential Revision: D68606631

Pulled By: xiaoxmeng

fbshipit-source-id: d0ef042c5ee935a598637b07549c9c48a06708fe

Author: zhztheplayer

CMake/VeloxUtils.cmake

@@ -77,9 +77,9 @@ function(velox_add_library TARGET)
       # Create the target if this is the first invocation.
       add_library(velox ${_type} ${ARGN})
       set_target_properties(velox PROPERTIES LIBRARY_OUTPUT_DIRECTORY
-                                             ${CMAKE_BINARY_DIR}/lib)
+                                             ${PROJECT_BINARY_DIR}/lib)
       set_target_properties(velox PROPERTIES ARCHIVE_OUTPUT_DIRECTORY
-                                             ${CMAKE_BINARY_DIR}/lib)
+                                             ${PROJECT_BINARY_DIR}/lib)
       install(TARGETS velox DESTINATION lib/velox)
     endif()
     # create alias for compatability