message: No longer tested with gcc4
diff: @@ -24,7 +24,7 @@ Build requirements
  ------------------
  - C++11 compliant compiler
  - (tested with g++-4.8.4 on Ubuntu 14.04 x86_64,
  + (tested with g++-5.4.0 on Ubuntu 16.04 x86_64,
  tested with clang-900.0.39.2 on Mac OS X 10.13,
  tested with Microsoft Visual Studio 2015 VC14 for x64)
  