solana-define-syscall is used at run time in 153 crates (of which 153 optionally). It is a direct run-time dependency in 9 crates. It's used only as a dev dependency in 4 crates.

Depender (with downloads and own rev deps) solana-define-syscall version
1.1M 546 solana-program =2.1.0
15K 1 solana-poseidon =2.1.0
6.3K 31 solana-pubkey =2.1.0
6.2K 9 solana-sha256-hasher =2.1.0
6.2K 18 solana-instruction =2.1.0
6.1K 11 solana-msg =2.1.0
6.1K 4 solana-program-memory =2.1.0
6.0K 3 solana-cpi =2.1.0
6.0K 2 solana-secp256k1-recover =2.1.0