r181397 of src/usr.bin/make/job.c breaks cross-compiles

[Bruce M Simpson]

Hi Andrey,

I see a change from you to job.c which is part of make...

When cross-building a make as part of a NanoBSD arm job (amd64 
7.1-PRERELEASE hosting an arm -CURRENT build), this change appears to 
break buildworld. If I back out this change and go back to rev 176808, 
the buildworld is fine.

I don't understand what arc4random_uniform() is or its benefit -- I'm 
guessing it just acts as a uniform distribution filtering interface to 
arc4random() -- however the interface doesn't appear to present prior to 
-CURRENT, and this is breaking stuff which should work.

Perhaps this change should be wrapped in an #if __FreeBSD_Version 
conditional so that it doesn't break 7.1->8.x source upgrades?

thanks,
BMS