Trying to fix random number generator for MinGW

It always returned the same value.
8 jobs for master in 3 minutes and 56 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #15994
linux
build:linux

00:01:25

passed #15993
mac_old
build:mac

00:01:56

passed #15992
win32
build:win32

00:01:03

passed #15991
winxp
build:winxp

00:01:13

 
  Dist
passed #15998
linux
dist:linux

00:00:16

passed #15997
mac_old
dist:mac

00:01:36

passed #15996
win32
dist:win32

00:00:15

passed #15995
winxp
dist:winxp

00:00:13