Try fixing clang builds

code/Profiler.h

@@ -83,7 +83,7 @@ public:
             return;
         }
 
-        std::chrono::duration<double> elapsedSeconds = std::chrono::system_clock::now() - regions[region];
+        auto elapsedSeconds = std::chrono::system_clock::now() - regions[region];
         DefaultLogger::get()->debug((format("END   `"),region,"`, dt= ", elapsedSeconds.count()," s"));
     }
 

include/assimp/defs.h

@@ -219,9 +219,9 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
      * without threading support. The library doesn't utilize
      * threads then and is itself not threadsafe. */
     //////////////////////////////////////////////////////////////////////////
-// #ifndef ASSIMP_BUILD_SINGLETHREADED
-// #   define ASSIMP_BUILD_SINGLETHREADED
-// #endif
+#ifndef ASSIMP_BUILD_SINGLETHREADED
+#   define ASSIMP_BUILD_SINGLETHREADED
+#endif
 
 #if defined(_DEBUG) || ! defined(NDEBUG)
 #   define ASSIMP_BUILD_DEBUG