decoder. There's no danger of information leak here, so
it isn't required. Doing memzero() takes a lot of time
with large dictionaries, which could make it easier to
construct DoS attack to consume too much CPU time.
These changes implement support for LZMA_SYNC_FLUSH in LZMA
encoder, and move the temporary buffer needed by range encoder
from lzma_range_encoder structure to lzma_lz_encoder.
