diff -Naur jdk12u-jdk-12.0.2+10.orig/src/jdk.sctp/unix/native/libsctp/Sctp.h jdk12u-jdk-12.0.2+10/src/jdk.sctp/unix/native/libsctp/Sctp.h
--- jdk12u-jdk-12.0.2+10.orig/src/jdk.sctp/unix/native/libsctp/Sctp.h	2019-07-16 18:38:28.000000000 +0200
+++ jdk12u-jdk-12.0.2+10/src/jdk.sctp/unix/native/libsctp/Sctp.h	2021-11-28 17:16:57.454740208 +0100
@@ -322,12 +322,12 @@
 
 #endif /* __linux__ */
 
-sctp_getladdrs_func* nio_sctp_getladdrs;
-sctp_freeladdrs_func* nio_sctp_freeladdrs;
-sctp_getpaddrs_func* nio_sctp_getpaddrs;
-sctp_freepaddrs_func* nio_sctp_freepaddrs;
-sctp_bindx_func* nio_sctp_bindx;
-sctp_peeloff_func* nio_sctp_peeloff;
+extern sctp_getladdrs_func* nio_sctp_getladdrs;
+extern sctp_freeladdrs_func* nio_sctp_freeladdrs;
+extern sctp_getpaddrs_func* nio_sctp_getpaddrs;
+extern sctp_freepaddrs_func* nio_sctp_freepaddrs;
+extern sctp_bindx_func* nio_sctp_bindx;
+extern sctp_peeloff_func* nio_sctp_peeloff;
 
 jboolean loadSocketExtensionFuncs(JNIEnv* env);
 
diff -Naur jdk12u-jdk-12.0.2+10.orig/src/jdk.sctp/unix/native/libsctp/SctpNet.c jdk12u-jdk-12.0.2+10/src/jdk.sctp/unix/native/libsctp/SctpNet.c
--- jdk12u-jdk-12.0.2+10.orig/src/jdk.sctp/unix/native/libsctp/SctpNet.c	2019-07-16 18:38:28.000000000 +0200
+++ jdk12u-jdk-12.0.2+10/src/jdk.sctp/unix/native/libsctp/SctpNet.c	2021-11-28 17:17:28.778497579 +0100
@@ -43,6 +43,13 @@
 static const char* nativeSctpLib = "libsctp.so.1";
 static jboolean funcsLoaded = JNI_FALSE;
 
+sctp_getladdrs_func* nio_sctp_getladdrs;
+sctp_freeladdrs_func* nio_sctp_freeladdrs;
+sctp_getpaddrs_func* nio_sctp_getpaddrs;
+sctp_freepaddrs_func* nio_sctp_freepaddrs;
+sctp_bindx_func* nio_sctp_bindx;
+sctp_peeloff_func* nio_sctp_peeloff;
+
 JNIEXPORT jint JNICALL DEF_JNI_OnLoad
   (JavaVM *vm, void *reserved) {
     return JNI_VERSION_1_2;