error: implicit declaration of function 'mkdtemp' is invalid in C99 #1308
Fails to build from source on macOS (MacPorts or manual).
Steps to reproduce
1. Update MacPorts Portfile to use official 2.4 tarball
It comes from unistd.h in Xcode 10.1.
Quick patch for 10.11.6 until it's fixed in upstream: