Modified C++ options on Mac for Debug build

Dropped those strange warning options and turned on -O1
8 jobs for master in 4 minutes (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #15695
linux
build:linux

00:01:26

passed #15694
mac_old
build:mac

00:02:03

passed #15693
win32
build:win32

00:01:04

passed #15692
winxp
build:winxp

00:01:13

 
  Dist
passed #15699
linux
dist:linux

00:00:16

passed #15698
mac_old
dist:mac

00:01:40

passed #15697
win32
dist:win32

00:00:15

passed #15696
winxp
dist:winxp

00:00:14