C++: Add test with missing flow through 'fopen'.

Author: MathiasVP

cpp/ql/test/library-tests/dataflow/taint-tests/localTaint.expected

@@ -6584,6 +6584,15 @@ WARNING: module 'TaintTracking' has been deprecated and may be removed in future
 | taint.cpp:767:21:767:24 | ref arg path | taint.cpp:768:8:768:11 | path |  |
 | taint.cpp:768:8:768:11 | path | taint.cpp:768:7:768:11 | * ... |  |
 | taint.cpp:778:37:778:42 | call to source | taint.cpp:779:7:779:9 | obj |  |
+| taint.cpp:785:23:785:28 | source | taint.cpp:785:23:785:28 | source |  |
+| taint.cpp:785:23:785:28 | source | taint.cpp:786:18:786:23 | source |  |
+| taint.cpp:785:23:785:28 | source | taint.cpp:790:15:790:20 | source |  |
+| taint.cpp:786:12:786:16 | call to fopen | taint.cpp:787:7:787:7 | f |  |
+| taint.cpp:789:8:789:9 | f2 | taint.cpp:790:11:790:12 | f2 |  |
+| taint.cpp:789:8:789:9 | f2 | taint.cpp:791:7:791:8 | f2 |  |
+| taint.cpp:790:10:790:12 | ref arg & ... | taint.cpp:790:11:790:12 | f2 [inner post update] |  |
+| taint.cpp:790:10:790:12 | ref arg & ... | taint.cpp:791:7:791:8 | f2 |  |
+| taint.cpp:790:11:790:12 | f2 | taint.cpp:790:10:790:12 | & ... |  |
 | vector.cpp:16:43:16:49 | source1 | vector.cpp:17:26:17:32 | source1 |  |
 | vector.cpp:16:43:16:49 | source1 | vector.cpp:31:38:31:44 | source1 |  |
 | vector.cpp:17:21:17:33 | call to vector | vector.cpp:19:14:19:14 | v |  |

cpp/ql/test/library-tests/dataflow/taint-tests/taint.cpp

@@ -777,4 +777,16 @@ TaintInheritingContentObject source(bool);
 void test_TaintInheritingContent() {
 	TaintInheritingContentObject obj = source(true);
 	sink(obj.flowFromObject); // $ ir MISSING: ast
+}
+
+FILE* fopen(const char*, const char*);
+int fopen_s(FILE** pFile, const char *filename, const char *mode);
+
+void fopen_test(char* source) {
+	FILE* f = fopen(source, "r");
+	sink(f); // $ MISSING: ast,ir
+
+	FILE* f2;
+	fopen_s(&f2, source, "r");
+	sink(f2); // $ ast MISSING: ir
 }