update macOS gcc@5 installation guide (dmlc#3003)

After installing ``gcc@5``, ``CMAKE_C_COMPILER`` will not be set to gcc-5 in some macOS environment automatically and the installation of xgboost will still fail. Manually setting the compiler will solve the problem.
machine4life · Jan 4, 2018 · bf43671 · bf43671
1 parent 14c6392
commit bf43671
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/python-package/README.rst b/python-package/README.rst
@@ -26,6 +26,11 @@ Please install ``gcc@5`` from `Homebrew <https://brew.sh/>`_::
 
     brew install gcc@5
 
+After installing ``gcc@5``, set it as your compiler::
+
+    export CC = gcc-5
+    export CXX = g++-5
+
 Linux
 -----