This ensures the symbols aren't redefined, which would result in a compiler
error.
I was getting redefined symbols for _LARGEFILE64_SOURCE when building for
32-bit x86 Linux on an older CentOS release in a CI environment. With this
change, I'm able to compile the single file library in this environment.
Closes#2443.
When porting python-zstandard to use ZSTD_initCStream_usingCDict()
so compression dictionaries could be reused, an automated test
failed due to compressed content changing.
I tracked this down to ZSTD_initCStream_usingCDict() not
setting the dictID field of the ZSTD_CCtx attached to the
ZSTD_CStream instance.
I'm not 100% convinced this is the correct or full solution,
as I'm still seeing one automated test failing with this change.
Gregory Szorc