Fix a clang/win build error
Fix a clang/win build error

Made the definition of THREAD_FUNCTION consistent.

Change-Id: I1ac099484e201e359298ed16de0b81ec781075ce

webmproject/libvpx,ittiamvpx/libvpx-1,luctrudeau/aom,mwgoldsmith/vpx,mwgoldsmith/libvpx,webmproject/libvpx,mbebenita/aom,Topopiccione/libvpx,mwgoldsmith/libvpx,Topopiccione/libvpx,GrokImageCompression/aom,mwgoldsmith/libvpx,luctrudeau/aom,webmproject/libvpx,smarter/aom,ShiftMediaProject/libvpx,ittiamvpx/libvpx-1,luctrudeau/aom,mwgoldsmith/libvpx,ShiftMediaProject/libvpx,mbebenita/aom,smarter/aom,Topopiccione/libvpx,Topopiccione/libvpx,smarter/aom,mbebenita/aom,mbebenita/aom,smarter/aom,ittiamvpx/libvpx-1,ShiftMediaProject/libvpx,mwgoldsmith/vpx,GrokImageCompression/aom,GrokImageCompression/aom,mbebenita/aom,ShiftMediaProject/libvpx,mwgoldsmith/vpx,mwgoldsmith/vpx,webmproject/libvpx,luctrudeau/aom,webmproject/libvpx,mwgoldsmith/libvpx,ittiamvpx/libvpx-1,GrokImageCompression/aom,Topopiccione/libvpx,ittiamvpx/libvpx-1,webmproject/libvpx,mwgoldsmith/vpx,ShiftMediaProject/libvpx,Topopiccione/libvpx,GrokImageCompression/aom,smarter/aom,GrokImageCompression/aom,mbebenita/aom,mbebenita/aom,luctrudeau/aom,smarter/aom,luctrudeau/aom,mbebenita/aom,mwgoldsmith/libvpx,ittiamvpx/libvpx-1,mwgoldsmith/vpx,mbebenita/aom