See
https://bugs.alpinelinux.org/issues/7041
https://git.alpinelinux.org/cgit/aports/commit/?id=9edb53cea056101c4963a04b747bf102de23f919
(just hit this myself when building libnsl)
... dilfridge

--- a/src/libtirpc.map
+++ b/src/libtirpc.map
@@ -298,7 +298,7 @@
     key_gendes;
     key_get_conv;
     key_setsecret;
-    key_secret_is_set;
+    key_secretkey_is_set;
     key_setnet;
     netname2host;
     netname2user;