Do you mean statically linked binaries? Fat binaries generally refer to multiple ABIs in the same image, a mostly Apple thing these days.
Golang produces one single binary you can deploy to your target environment and doesn't really require anything else installed.
From what I've read, Crystal generates a binary but you also need to ensure Crystal is installed on your target environment.
By default, Crystal generates dynamically linked binaries. You absolutely do not need Crystal to run them. But you do need:
- Boehm GC (libgc-threaded)
- libevent
- PCRE if the program uses regexps
- libyaml if the program uses yaml
- OpenSSL if the program uses crypto/TLS (?)
Here's an example ldd output:
/usr/local/bin/shards:
libyaml-0.so.2 => /usr/local/lib/libyaml-0.so.2 (0x8c0bb1e000)
libpcre.so.1 => /usr/local/lib/libpcre.so.1 (0x8c0bd3c000)
libm.so.5 => /lib/libm.so.5 (0x8c0bfb8000)
libgc-threaded.so.1 => /usr/local/lib/libgc-threaded.so.1 (0x8c0c1e6000)
libthr.so.3 => /lib/libthr.so.3 (0x8c0c444000)
libevent-2.1.so.6 => /usr/local/lib/libevent-2.1.so.6 (0x8c0c66c000)
libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x8c0c8c3000)
libc.so.7 => /lib/libc.so.7 (0x8c0cad2000)
libdl.so.1 => /usr/lib/libdl.so.1 (0x8c0ce8f000)
libcrypto.so.42 => /usr/local/lib/libcrypto.so (0x8c0d091000)