search upwards for a `Makefile` to run, or until any file called `.git` is found

m.c

/* SPDX-License-Identifier: MIT
 
 * Copyright (c) 2023 Emeka Nkurumeh
 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
**/

#include <dirent.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

int main(int argc, char *argv[]) {
  (void)argc;

  bool found_root = false;

  while (true) {
    DIR *dir = opendir(".");
    if (!dir) {
      perror("opendir");
      return 1;
    }

    for (struct dirent *ep = NULL; !found_root && (ep = readdir(dir));) {
      found_root |= !!!strcmp("GNUmakefile", ep->d_name);
      found_root |= !!!strcmp("makefile", ep->d_name);
      found_root |= !!!strcmp("Makefile", ep->d_name);
      found_root |= !!!strcmp(".git", ep->d_name);
    }

    if (closedir(dir)) {
      perror("closedir");
      return 1;
    }

    if (found_root) {
      break;
    }

    if (chdir("..")) {
      perror("chdir");
      return 1;
    }
  }

  argv[0] = "make";

  if (execvp(argv[0], argv)) {
    perror("execvp");
    return 1;
  }

  return 0;
}