message: CMake: make shared libs work again.
  BUILD_SHARED_LIBS got renamed to MESHOPT_BUILD_SHARED_LIBS, but the
  unprefixed variant is what needs to be set for add_library() to work as
  desired.
diff: @@ -16,6 +16,11 @@ option(MESHOPT_BUILD_TOOLS "Build tools" OFF)
  option(MESHOPT_BUILD_SHARED_LIBS "Build shared libraries" OFF)
  set(MESHOPT_BUILD_TOOLS_GLFW_FOLDER_NAME "" CACHE STRING "Custom folder to look for GLFW")
  +# add_library() needs BUILD_SHARED_LIBS set to decide between static and
  +# shared. This also sets it back to OFF in case parent project has
  +# BUILD_SHARED_LIBS but wants MESHOPT_BUILD_SHARED_LIBS to be OFF.
  +set(BUILD_SHARED_LIBS ${MESHOPT_BUILD_SHARED_LIBS})
  +
  set(SOURCES
  src/meshoptimizer.h
  src/allocator.cpp
  