Check attached build log. Note: I killed the build because scons seems to have frozen at that point, no clue why.
Created attachment 184018 [details] Build log
Dear upstream...will you prepare a fix or should we wait for the successor that will have that fixed?
Seems doubtful anyone's gonna fix this, so either just filter/deactivate the flag, compile with a different compiler or deactivate/use-flag the "linux-urandom" module in einit's sconscript. the successor shouldn't have this particular issue.
Created attachment 184628 [details, diff] fix for O_CREAT bug in src/modules/linux/linux-urandom.c
Patch looks good to me, please test.