message: [waf] Add -std=c++11 when CXXFLAGS is specified without -std= setting
diff: @@ -137,6 +137,8 @@ def configure(ctx):
  # If environment variable CXXFLAGS is unset, provide a sane default.
  if not ctx.env.CXXFLAGS:
  ctx.env.CXXFLAGS = cxxflags
  + elif all(not x.startswith('-std=') for x in ctx.env.CXXFLAGS):
  + ctx.env.CXXFLAGS.append('-std=c++11')
  if not ctx.env.LDFLAGS:
  ctx.env.LDFLAGS = ldflags
  else:
  