Maximum output size with a 32-bit int is 17 bytes, or 26 with a 64-bit
int.

Silences the following gcc 10 warning:
src/libavdevice/jack.c: In function ‘audio_read_header’:
src/libavdevice/jack.c:171:45: warning: ‘snprintf’ output may be truncated before the last format character [-Wformat-truncation=]
  171 |         snprintf(str, sizeof(str), "input_%d", i + 1);
      |                                             ^
src/libavdevice/jack.c:171:9: note: ‘snprintf’ output between 8 and 17 bytes into a destination of size 16
  171 |         snprintf(str, sizeof(str), "input_%d", i + 1);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~