Newer curl versions (as used on macOS via Homebrew) add attributes like __attribute__ ((format(printf, a, b))) to their `curl_*printf*` functions, which fails if we redefine `printf` as e.g. `builtin_printf` (pulled in via library.h). We could disable these checks via CURL_NO_FMT_CHECKS, but reordering the headers should do the trick as well.