gambc 4.8.8-3 (armhf binary) in ubuntu bionic

 The gambc package includes a Scheme interpreter and a Scheme compiler which
 can be used to build standalone executables. The thread system is very
 efficient and can support millions of concurrent processes.
 .
 The Gambit system conforms to the R4RS, R5RS and IEEE Scheme standards. The
 full numeric tower is implemented, including: infinite precision integers
 (bignums), rationals, inexact reals (floating point numbers), and complex
 numbers. Gambit supports a number of extensions to the standards.