Delete LIBC_CALLS_HEFTY

- fork() no longer requires malloc()
- readdir() moved to LIBC_STDIO
- Custom APIs moved to LIBC_X

libc/stdio/get_current_dir_name.c

@@ -0,0 +1,38 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/bits/safemacros.h"
+#include "libc/calls/calls.h"
+#include "libc/mem/mem.h"
+#include "libc/runtime/runtime.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Returns current working directory.
+ *
+ * If the PWD environment variable is set, that'll be returned (since
+ * it's faster than issuing a system call).
+ *
+ * @return pointer that must be free()'d, or NULL w/ errno
+ */
+nodiscard char *get_current_dir_name(void) {
+  char *buf, *res;
+  if (!(buf = malloc(PATH_MAX))) return NULL;
+  if (!(res = (getcwd)(buf, PATH_MAX))) free(buf);
+  return res;
+}