While running make check, I get the error in the title. I believe this was caused by c7dd7fbc8b7010ac70eb9c5b20c7f66af2cc6ce4 "add gst-remote tool", as that added unistd.h, which includes getopt.h on my system (presumably to provide the `getopt' function as required by POSIX). A zip includes gst-tool.c preprocessed and my unistd.h (see line 837).