libcryptsetup: drop several unnecessary checks for existences of functions by libcryptsetyp

The functions crypt_set_metadata_size() and friends are supported since
libcryptsetup-2.0.

This also merges checks for functions used for supporting libcryptsetup
plugins with others.
Moreover, check existence of one more function (crypt_logf) that is used in
libcryptsetup plugins.

src/shared/cryptsetup-util.h

@@ -16,9 +16,7 @@
 #endif
 
 extern DLSYM_PROTOTYPE(crypt_activate_by_passphrase);
-#if HAVE_CRYPT_ACTIVATE_BY_SIGNED_KEY
 extern DLSYM_PROTOTYPE(crypt_activate_by_signed_key);
-#endif
 extern DLSYM_PROTOTYPE(crypt_activate_by_volume_key);
 extern DLSYM_PROTOTYPE(crypt_deactivate_by_name);
 extern DLSYM_PROTOTYPE(crypt_format);
@@ -39,15 +37,11 @@ extern DLSYM_PROTOTYPE(crypt_keyslot_destroy);
 extern DLSYM_PROTOTYPE(crypt_keyslot_max);
 extern DLSYM_PROTOTYPE(crypt_load);
 extern DLSYM_PROTOTYPE(crypt_resize);
-#if HAVE_CRYPT_RESUME_BY_VOLUME_KEY
 extern DLSYM_PROTOTYPE(crypt_resume_by_volume_key);
-#endif
 extern DLSYM_PROTOTYPE(crypt_set_data_device);
 extern DLSYM_PROTOTYPE(crypt_set_debug_level);
 extern DLSYM_PROTOTYPE(crypt_set_log_callback);
-#if HAVE_CRYPT_SET_METADATA_SIZE
 extern DLSYM_PROTOTYPE(crypt_set_metadata_size);
-#endif
 extern DLSYM_PROTOTYPE(crypt_set_pbkdf_type);
 extern DLSYM_PROTOTYPE(crypt_suspend);
 extern DLSYM_PROTOTYPE(crypt_token_json_get);
@@ -64,18 +58,14 @@ extern DLSYM_PROTOTYPE(crypt_token_set_external_path);
 #endif
 extern DLSYM_PROTOTYPE(crypt_token_status);
 extern DLSYM_PROTOTYPE(crypt_volume_key_get);
-#if HAVE_CRYPT_REENCRYPT_INIT_BY_PASSPHRASE
 extern DLSYM_PROTOTYPE(crypt_reencrypt_init_by_passphrase);
-#endif
 #if HAVE_CRYPT_REENCRYPT_RUN
 extern DLSYM_PROTOTYPE(crypt_reencrypt_run);
-#elif HAVE_CRYPT_REENCRYPT
+#else
 extern DLSYM_PROTOTYPE(crypt_reencrypt);
 #endif
 extern DLSYM_PROTOTYPE(crypt_metadata_locking);
-#if HAVE_CRYPT_SET_DATA_OFFSET
 extern DLSYM_PROTOTYPE(crypt_set_data_offset);
-#endif
 extern DLSYM_PROTOTYPE(crypt_header_restore);
 extern DLSYM_PROTOTYPE(crypt_volume_key_keyring);