Bug in RAR5 solid files

[DrMcCoy]

While testing for #4, I noticed a bug in our handling of RAR5 solid files. Sometimes, we produce broken output.

Example:
1.txt
blah
2.txt
foo

rar -ma5 -s a test.rar 1.txt 2.txt

This creates a solid RAR5 file we can't correctly decompress. The first file extracts fine, the second doesn't. Seems to be connected to our "finishing off" of the remaining of the solid block. I assume it produces output that belongs into the second file instead of just influencing the state?

[DrMcCoy]

As an update of sorts, I haven't yet found an easy way to fix this. It looks like I'll need to take apart solid file support and redo it mostly from scratch. I was basing it on partially wrong assumptions.

As a consequence, solid files are partially broken at the moment still. Partially meaning, it might work depending on the files that are bundled together in a solid chunk. Tiny files in particular are more prone to breaking. dmc_unrar isn't silently producing broken files, however, at least not as long as checksum validation is enabled.