dovecot-openssl-common.c:61:31: warning: incompatible pointer types passing 'void *(size_t)' (aka 'void *(unsigned long)') to parameter of type 'void *(*)(size_t, const char *, int)' (aka 'void *(*)(unsigned long, const char *, int)') [-Wincompatible-pointer-types]
        if (CRYPTO_set_mem_functions(dovecot_openssl_malloc,
                                     ^~~~~~~~~~~~~~~~~~~~~~
/opt/openssl/include/openssl/crypto.h:262:17: note: passing argument to parameter 'm' here
        void *(*m) (size_t, const char *, int),
                ^

dovecot-openssl-common.c:62:10: warning: incompatible pointer types passing 'void *(void *, size_t)' (aka 'void *(void *, unsigned long)') to parameter of type 'void *(*)(void *, size_t, const char *, int)' (aka 'void *(*)(void *, unsigned long, const char *, int)') [-Wincompatible-pointer-types]
                                     dovecot_openssl_realloc, dovecot_openssl_free) == 0) {
                                     ^~~~~~~~~~~~~~~~~~~~~~~
/opt/openssl/include/openssl/crypto.h:263:17: note: passing argument to parameter 'r' here
        void *(*r) (void *, size_t, const char *, int),
                ^

dovecot-openssl-common.c:62:35: warning: incompatible pointer types passing 'void (void *)' to parameter of type 'void (*)(void *, const char *, int)' [-Wincompatible-pointer-types]
                                     dovecot_openssl_realloc, dovecot_openssl_free) == 0) {
                                                              ^~~~~~~~~~~~~~~~~~~~
/opt/openssl/include/openssl/crypto.h:264:16: note: passing argument to parameter 'f' here
        void (*f) (void *, const char *, int));
               ^

3 warnings generated.