There is a small typo in src/src/globals.h.
Should read `signature` rather than `signture`.
extern uschar *dkim_verify_hashes; /* Preference order for signatures */
extern uschar *dkim_verify_keytypes; /* Preference order for signatures */
extern uschar *dkim_verify_min_keysizes; /* list of minimum key sizes, keyed by algo */
-extern BOOL dkim_verify_minimal; /* Shortcircuit signture verification */
+extern BOOL dkim_verify_minimal; /* Shortcircuit signature verification */
extern uschar *dkim_verify_overall; /* First successful domain verified, or null */
extern uschar *dkim_verify_signers; /* Colon-separated list of domains for each of which we call the DKIM ACL */
extern uschar *dkim_verify_status; /* result for this signature */