Add no_std support

[bjorn3]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 93.14286% with 24 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
bzlib.rs	90.25%	15 Missing ⚠️
blocksort.rs	94.15%	9 Missing ⚠️

Files with missing lines	Coverage Δ
c2rust-lib.rs	98.21% <100.00%> (ø)
compress.rs	99.63% <100.00%> (+<0.01%)	⬆️
decompress.rs	94.13% <100.00%> (ø)
blocksort.rs	97.52% <94.15%> (-0.40%)	⬇️
bzlib.rs	88.35% <90.25%> (+<0.01%)	⬆️