Add include of config.h and WORDS_BIGENDIAN check to blake2-impl.h.
Add include of config.h and WORDS_BIGENDIAN check to blake2-impl.h.

sourcefrog/librsync,dbaarda/librsync,dbaarda/librsync,librsync/librsync,sourcefrog/librsync,librsync/librsync,librsync/librsync,sourcefrog/librsync,sourcefrog/librsync,dbaarda/librsync,dbaarda/librsync,librsync/librsync