If you get the following error:

In function "open",
inlined from "log_open" at ec_log.c:193:
/usr/include/bits/fcntl2.h:51: error: call to "__open_missing_mode" declared with attribute error: open with O_CREAT in second argument needs 3 arguments

You will need to change the following line in src/ec_log.c:
fd->fd = open(filename, O_CREAT | O_TRUNC | O_RDWR | O_BINARY);
into:
fd->fd = open(filename, O_CREAT | O_TRUNC | O_RDWR | O_BINARY, 0666);