Disabling warning C4251 under MSVC

8 jobs for master in 4 minutes and 11 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #12772
linux
build:linux

00:01:24

passed #12771
mac_old
build:mac

00:01:36

passed #12770
win32
build:win32

00:01:04

passed #12769
winxp
build:winxp

00:01:15

 
  Dist
passed #12776
linux
dist:linux

00:00:16

passed #12775
mac_old
dist:mac

00:01:50

passed #12774
win32
dist:win32

00:00:16

passed #12773
winxp
dist:winxp

00:00:17