They're not kidding when they call it an ecosystem for developing new languages (indeed, racket itself is on some bleeding edges of language research, notably in the area of sound gradual typing with the ongoing typed racket project). Many Racketeers are researchers who take metaprogramming very seriously.
Racket currently uses the GNU lightning VM[1] via a JIT compiler, but is migrating onto the recently much-less-encumbered Chez (thanks, Cisco!).
Lightning and Chez both provide AOT features that Racket can use, although neither can really do source-to-source translation of Racket to C.
If you really want a modern scheme->C, then Chicken Scheme https://www.call-cc.org/ is your best bet. It gains some advantages by using (highly idiomatic) C as an intermediate language, but unfortunately then has to contend with C language idioms and constraints, especially C's runtime, which strongly constrains Chicken's approaches to concurrency.
I find it difficult to imagine that anyone will sit down and write a scheme->C compiler that produces human-readable C. You can see for yourself what Chicken emits, and that's still much more readable than the long-dead DEC Scheme->C's output.
Lastly, doing serious systems programming in Scheme is both feasible and has even been done. Sadly one extremely interesting example of this is decaying at http://www.scsh.net/ (the links to Shivers's papers are broken, and frankly they were the most entertaining parts of SCSH) although some ideas originating in SCSH have been ported to other Scheme implementations.
You know about Racket, right?
https://racket-lang.org/
They're not kidding when they call it an ecosystem for developing new languages (indeed, racket itself is on some bleeding edges of language research, notably in the area of sound gradual typing with the ongoing typed racket project). Many Racketeers are researchers who take metaprogramming very seriously.
Racket currently uses the GNU lightning VM[1] via a JIT compiler, but is migrating onto the recently much-less-encumbered Chez (thanks, Cisco!).
https://groups.google.com/forum/#!msg/racket-dev/2BV3ElyfF8Y...
Recent update!
https://groups.google.com/forum/#!topic/racket-dev/rkXuHNAmQ...
Lightning and Chez both provide AOT features that Racket can use, although neither can really do source-to-source translation of Racket to C.
If you really want a modern scheme->C, then Chicken Scheme https://www.call-cc.org/ is your best bet. It gains some advantages by using (highly idiomatic) C as an intermediate language, but unfortunately then has to contend with C language idioms and constraints, especially C's runtime, which strongly constrains Chicken's approaches to concurrency.
I find it difficult to imagine that anyone will sit down and write a scheme->C compiler that produces human-readable C. You can see for yourself what Chicken emits, and that's still much more readable than the long-dead DEC Scheme->C's output.
Lastly, doing serious systems programming in Scheme is both feasible and has even been done. Sadly one extremely interesting example of this is decaying at http://www.scsh.net/ (the links to Shivers's papers are broken, and frankly they were the most entertaining parts of SCSH) although some ideas originating in SCSH have been ported to other Scheme implementations.
[1] kinda. http://lists.racket-lang.org/dev/archive//2014-September/014...