fix: added header guards, and some testing purpose autotools rules

src/ast/ast.h

@@ -0,0 +1,22 @@
+#ifndef AST_H
+#define AST_H
+
+
+enum ast_type
+{
+    AST_NULL = 0,
+    ATS_IF,
+    AST_CMD
+};
+
+union ast_union
+{
+};
+
+struct ast
+{
+    enum ast_type type;
+    union ast_union data;
+};
+
+#endif /* ! AST_H */