Add test for mismatched alignments on gcc

Author: MichaelRFairhurst

c/misra/test/rules/RULE-8-15/RedeclarationOfObjectWithUnmatchedAlignment.expected.gcc

@@ -0,0 +1,10 @@
+| test.c:11:8:11:15 | alignas(...) | Variable g4 declared with lexically different _Alignof() values '$@' and '$@' | test.c:11:8:11:15 | alignas(...) | 16 | test.c:12:8:12:15 | alignas(...) | 32 |
+| test.c:12:8:12:15 | alignas(...) | Variable g4 declared with lexically different _Alignof() values '$@' and '$@' | test.c:12:8:12:15 | alignas(...) | 32 | test.c:11:8:11:15 | alignas(...) | 16 |
+| test.c:18:8:18:15 | alignas(...) | Variable g6 declared with lexically different _Alignof() values '$@' and '$@' | test.c:18:8:18:15 | alignas(...) | int | test.c:19:8:19:15 | alignas(...) | 4 |
+| test.c:19:8:19:15 | alignas(...) | Variable g6 declared with lexically different _Alignof() values '$@' and '$@' | test.c:19:8:19:15 | alignas(...) | 4 | test.c:18:8:18:15 | alignas(...) | int |
+| test.c:22:8:22:15 | alignas(...) | Variable g7 declared with lexically different _Alignof() values '$@' and '$@' | test.c:22:8:22:15 | alignas(...) | ... * ... | test.c:23:8:23:15 | alignas(...) | 32 |
+| test.c:23:8:23:15 | alignas(...) | Variable g7 declared with lexically different _Alignof() values '$@' and '$@' | test.c:23:8:23:15 | alignas(...) | 32 | test.c:22:8:22:15 | alignas(...) | ... * ... |
+| test.c:28:8:28:15 | alignas(...) | Variable g9 declared with lexically different _Alignof() values '$@' and '$@' | test.c:28:8:28:15 | alignas(...) | ... * ... | test.c:29:8:29:15 | alignas(...) | ... * ... |
+| test.c:29:8:29:15 | alignas(...) | Variable g9 declared with lexically different _Alignof() values '$@' and '$@' | test.c:29:8:29:15 | alignas(...) | ... * ... | test.c:28:8:28:15 | alignas(...) | ... * ... |
+| test.c:34:8:34:15 | alignas(...) | Variable g11 declared with lexically different _Alignof() values '$@' and '$@' | test.c:34:8:34:15 | alignas(...) | signed int | test.c:35:8:35:15 | alignas(...) | unsigned int |
+| test.c:35:8:35:15 | alignas(...) | Variable g11 declared with lexically different _Alignof() values '$@' and '$@' | test.c:35:8:35:15 | alignas(...) | unsigned int | test.c:34:8:34:15 | alignas(...) | signed int |

c/misra/test/rules/RULE-8-15/test.c.gcc

@@ -0,0 +1,35 @@
+extern _Alignas(16) int g1; // COMPLIANT
+extern _Alignas(16) int g1; // COMPLIANT
+
+extern _Alignas(16) int g2;
+extern int g2; // NON_COMPLIANT
+
+extern int g3; // NON_COMPLIANT
+extern _Alignas(16) int g3;
+
+// Does not compile on clang:
+extern _Alignas(16) int g4; // COMPLIANT
+extern _Alignas(32) int g4; // COMPLIANT
+
+extern int g5; // COMPLIANT
+extern int g5; // COMPLIANT
+
+// Spec says elements must be lexically identical after macro expansion
+extern _Alignas(int) int g6; // NON_COMPLIANT
+extern _Alignas(4) int g6;   // NON_COMPLIANT
+
+#define THIRTY_TWO 32
+extern _Alignas(16 * 2) int g7; // NON_COMPLIANT
+extern _Alignas(32) int g7;     // NON_COMPLIANT
+
+extern _Alignas(THIRTY_TWO) int g8; // COMPLIANT
+extern _Alignas(32) int g8;         // COMPLIANT
+
+extern _Alignas(16 * 2) int g9; // NON_COMPLIANT
+extern _Alignas(2 * 16) int g9; // NON_COMPLIANT
+
+extern _Alignas(int) int g10; // COMPLIANT
+extern _Alignas(int) int g10; // COMPLIANT
+
+extern _Alignas(signed int) int g11;   // NON_COMPLIANT
+extern _Alignas(unsigned int) int g11; // NON_COMPLIANT