linters, some ast headers

main.c

@@ -5,7 +5,7 @@
 int zig1_run(char* program, char** msg);
 int zig1_run_file(char* fname, char** msg);
 
-static void usage(char* argv0)
+static void usage(const char* argv0)
 {
     fprintf(stderr, "Usage: %s program.zig\n", argv0);
 }