8238386: (sctp) jdk.sctp/unix/native/libsctp/SctpNet.c "multiple defi…

…nition" link errors with GCC10

Fixed libsctp link errors caused by GCC10 default -fno-common

Backport-of: 1d42f08

src/jdk.sctp/unix/native/libsctp/Sctp.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -322,12 +322,12 @@ typedef int sctp_peeloff_func(int sock, sctp_assoc_t id);
 
 #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);
 

src/jdk.sctp/unix/native/libsctp/SctpNet.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -43,6 +43,13 @@ static jmethodID isaCtrID = 0;
 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;