NIDAnalyzer: check that import thunk exists before renaming

Make sure the import thunk exists before attempting to rename it; otherwise, the analyzer will fail.
?Workaround for another bug?

src/main/java/vitaloaderredux/analyzer/NIDAnalyzer.java

@@ -165,7 +165,13 @@ private void analyzeFunction(IEType importOrExport, String libraryName, Address
 				func.setName(databaseName, SourceType.ANALYSIS);
 				if (importOrExport == IEType.IMPORT) {
 					//Set name for the thunk too
-					func.getThunkedFunction(true).setName(databaseName, SourceType.ANALYSIS);
+					Function thunk = func.getThunkedFunction(true);
+					if (thunk == null) {
+						helper.logf("Import thunk for %s_%08X (%s) not found (bug?)",
+							    libraryName, functionNID, databaseName);
+					} else {
+						thunk.setName(databaseName, SourceType.ANALYSIS);
+					}
 				}
 
 				helper.symTbl.createLabel(funcAddr, oldName, SourceType.ANALYSIS);