Signal errors with return codes?

While decompressing via JBlosc, I was hitting [a `-1` return value from because my "dest" buffer wasn't big enough](https://github.com/Blosc/c-blosc/blob/a60e30bf371b50dff22a50e224e95752ee41dfb5/blosc/blosc.c#L1446).

I'm responding to all `-1`s by exponentially increasing my buffer size until I hit 2GB-1, at which point I assume continued failure means the data is corrupt, but it would be nice to differentiate these cases via the return value.

Read blosc/blosc.c around line 1446 and the issue's decompression scenario. Clarify the return-code contract for an undersized dest buffer versus corrupt data, then add focused coverage showing both cases are distinguishable.

Written by the indexing model from the issue text.