libp2p: Check __BYTE_ORDER__ instead of __BYTE_ORDER.
libp2p: Check __BYTE_ORDER__ instead of __BYTE_ORDER.

Fixes bad planar RGB to packed RGB32 conversion on some OS X systems
due to incorrect endianness detection.

Kamekameha/vapoursynth,Kamekameha/vapoursynth,Kamekameha/vapoursynth,vapoursynth/vapoursynth,Kamekameha/vapoursynth,vapoursynth/vapoursynth,vapoursynth/vapoursynth,vapoursynth/vapoursynth