[PATH] fix broken mac build on old clangs.

[Dirk Hohndel]

> On Nov 8, 2015, at 19:31, Thiago Macieira <thiago at macieira.org> wrote:
> 
>> On Sunday 08 November 2015 22:12:19 Tomaz Canabrava wrote:
>> if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
>> -       set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu11 ")
>> -       set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
>> +       set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu99 ")
>> elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang")
>> -       set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu11 ")
>> -       set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
>> +       set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu99 ")
> 
> Why? Anyone using Clang has a recent enough version of it that it supports 
> C++11.

Nope. Xcode 4 uses clang and throws up with c++11

And I need XCode 4 to build working binaries. We've been down this rat hole before. I'm not switching compilers. 

/D