libsepol: silence -Wextra-semi-stmt warning

On Ubuntu 20.04, when building with clang -Werror -Wextra-semi-stmt
(which is not the default build configuration), the compiler reports:

  ../cil/src/cil_binary.c:4293:22: error: empty expression statement
  has no effect; remove unnecessary ';' to silence this warning
  [-Werror,-Wextra-semi-stmt]
          mix(k->target_class);
                              ^
  ../cil/src/cil_binary.c:4294:21: error: empty expression statement
  has no effect; remove unnecessary ';' to silence this warning
  [-Werror,-Wextra-semi-stmt]
          mix(k->target_type);
                             ^
  ../cil/src/cil_binary.c:4295:21: error: empty expression statement
  has no effect; remove unnecessary ';' to silence this warning
  [-Werror,-Wextra-semi-stmt]
          mix(k->source_type);
                             ^
  ../cil/src/cil_binary.c:4296:19: error: empty expression statement
  has no effect; remove unnecessary ';' to silence this warning
  [-Werror,-Wextra-semi-stmt]
          mix(k->specified);
                           ^

Use a do { ... } while (0) construction to silence this warning.

Moreover the same warning appears when using two semicolons to end a
statement. Remove such occurrences, like what was already done in commit
8111856 ("libsepol: drop repeated semicolons").

Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>

libsepol/cil/src/cil_binary.c

@@ -4277,15 +4277,15 @@ static unsigned int avrulex_hash(__attribute__((unused)) hashtab_t h, const_hash
 
 	uint32_t hash = 0;
 
-#define mix(input) { \
+#define mix(input) do { \
 	uint32_t v = input; \
 	v *= c1; \
 	v = (v << r1) | (v >> (32 - r1)); \
 	v *= c2; \
 	hash ^= v; \
 	hash = (hash << r2) | (hash >> (32 - r2)); \
 	hash = hash * m + n; \
-}
+} while (0)
 
 	mix(k->target_class);
 	mix(k->target_type);

libsepol/cil/src/cil_resolve_ast.c

@@ -2825,7 +2825,7 @@ static int cil_build_call_args(struct cil_tree_node *call_node, struct cil_call
 			return SEPOL_OK;
 		} else {
 			cil_tree_log(call_node, CIL_ERR, "Unexpected arguments");
-			return SEPOL_ERR;;
+			return SEPOL_ERR;
 		}
 	}
 	if (call->args_tree == NULL) {

libsepol/src/avtab.c

@@ -63,15 +63,15 @@ static inline int avtab_hash(struct avtab_key *keyp, uint32_t mask)
 
 	uint32_t hash = 0;
 
-#define mix(input) { \
+#define mix(input) do { \
 	uint32_t v = input; \
 	v *= c1; \
 	v = (v << r1) | (v >> (32 - r1)); \
 	v *= c2; \
 	hash ^= v; \
 	hash = (hash << r2) | (hash >> (32 - r2)); \
 	hash = hash * m + n; \
-}
+} while (0)
 
 	mix(keyp->target_class);
 	mix(keyp->target_type);

libsepol/tests/libsepol-tests.c

@@ -36,13 +36,17 @@
 int mls;
 
 #define DECLARE_SUITE(name) \
-	suite = CU_add_suite(#name, name##_test_init, name##_test_cleanup); \
-	if (NULL == suite) { \
-		CU_cleanup_registry(); \
-		return CU_get_error(); } \
-	if (name##_add_tests(suite)) { \
-		CU_cleanup_registry(); \
-		return CU_get_error(); }
+	do { \
+		suite = CU_add_suite(#name, name##_test_init, name##_test_cleanup); \
+		if (NULL == suite) { \
+			CU_cleanup_registry(); \
+			return CU_get_error(); \
+		} \
+		if (name##_add_tests(suite)) { \
+			CU_cleanup_registry(); \
+			return CU_get_error(); \
+		} \
+	} while (0)
 
 static void usage(char *progname)
 {