+#define LINE_GROWTH 16
+static int add_byte(int c, char **lineptr, size_t slen, size_t *n)
+{
+ char *nline;
+ size_t new_size = slen + 1;
+ if (new_size > *n) {
+ new_size += LINE_GROWTH - 1;
+ new_size *= 2;
+ nline = realloc(*lineptr, new_size);
+ if (!nline)
+ return -1;
+
+ *lineptr = nline;
+ *n = new_size;
+ }
+
+ (*lineptr)[slen] = c;
+
+ return 0;
+}
+
+static ssize_t compat_getline(char **lineptr, size_t *n, FILE *stream)
+{
+ char *line = *lineptr;
+ size_t slen = 0;
+
+ for (;;) {
+ int c = getc(stream);
+
+ switch (c) {
+ case '\n':
+ if (add_byte(c, &line, slen, n) < 0)
+ goto e_out;
+ slen++;
+ /* fall through */
+ case EOF:
+ if (add_byte('\0', &line, slen, n) < 0)
+ goto e_out;
+ *lineptr = line;
+ if (slen == 0)
+ return -1;
+ return slen;
+ default:
+ if (add_byte(c, &line, slen, n) < 0)
+ goto e_out;
+ slen++;
+ }
+ }
+
+e_out:
+ line[slen-1] = '\0';
+ *lineptr = line;
+ return -1;
+}
+