in custom commands generating such sources, but not
<code class="docutils literal notranslate"><span class="pre">PRE_BUILD</span></code>, <code class="docutils literal notranslate"><span class="pre">PRE_LINK</span></code>, or <code class="docutils literal notranslate"><span class="pre">POST_BUILD</span></code> commands.  Some native build
systems (such as Xcode) may not like targets that have only object files, so
consider adding at least one real source file to any target that references
<code class="docut