BUG in open() on a fifo with O_CREAT

My program was opening a fifo with these flags: O_NONBLOCK O_RDONLY and (by mistake) O_CREAT. It worked as I wanted until I tried it under Trisquel version 6, where it did a segfault. Apparently O_CREAT was being ignored under the older systems. Taking it out fixes the problem. I tried making a small test program, but instead of a segfault I get an abort with a complaint about no mode argument given with O_CREAT. If somebody thinks the segfault is worth tracking down I will supply complete information on the program which behaves that way.