[CentOS] compile webkit

I am trying to compile webkitgtk
I downloaded the webkit source, extracted

CMake Error at Source/cmake/OptionsGTK.cmake:12 (message):
  GCC 4.9.0 is required to build WebKitGTK+, use a newer GCC version or
clang

I downloaded 2.14.7 - just like CentOS 7.4 has, how can I be getting a GCC
error  ?


My goal is to get the MediaSource package in webkit working. It seems to
not be enabled.
Is there a better way ?

Thanks,

Jerry