Change std to gnu-c2x

Makefile

@@ -35,7 +35,7 @@ CFLAGS += -Wduplicated-cond -Wformat=2 -Wshadow -fno-builtin
 CFLAGS += -Wstrict-aliasing=0 -Wstrict-prototypes -Wunreachable-code
 CFLAGS += -Wwrite-strings -Werror=declaration-after-statement
 CFLAGS += -Werror=format-nonliteral -Werror=int-conversion -Werror=return-type
-CFLAGS += -Wno-discarded-qualifiers
+CFLAGS += -Wno-discarded-qualifiers --std=gnu2x
 
 LDFLAGS += -L .
 LDLIBS := -lu

src/ast/ast.c

@@ -170,10 +170,10 @@ ast_t *fill_semi_node(ast_ctx_t *ctx, ast_t *node)
         if (ctx->act_tok.type & (T_SEMICOLON | T_NEWLINE))
             continue;
         if (!ensure_list_cap(node))
-            return false;
+            return NULL;
         node->list.nodes[node->list.sz] = parse_semi(ctx);
         if (node->list.nodes[node->list.sz] == NULL)
-            return false;
+            return NULL;
         node->list.sz++;
     }
     return node;