Adding link options for userspace build

src/epics/util/lib/createUserModuleBuildEnv.pm

@@ -226,6 +226,10 @@ my ($makefileDir) = @_;
         print OUTM "list(APPEND LDFLAGS \"-L \${API_LIB_PATH}\")\n";
     }
 
+    if ($::extra_usp_linkoptions) {
+        print OUTM "list(APPEND LDFLAGS \"$::extra_usp_linkoptions\")\n";
+    }
+
     print OUTM "\n";
     close OUTM;
 }