Update Readme for CentOS 7.x

README.md

@@ -118,7 +118,25 @@ See __--enable-jnat__ below
 ### Building and config options
 
 The toolset is build upon the autotools framework. Run `./autogen.sh` first.
-Afterwards `./configure` `make` and `make install` should do the trick.
+Afterwards `./configure` `make` and `make install` should do the trick. 
+
+If you run CentOS 7.x you need to install a more recent compiler:
+
+```c
+yum install centos-release-scl
+```
+
+Then you can install GCC 8 and its C++ compiler:
+
+```c
+yum install devtoolset-8-gcc devtoolset-8-gcc-c++
+```
+
+To switch to a shell which defaults `gcc` and `g++` to this GCC version, use:
+
+```c
+scl enable devtoolset-8 -- bash
+```
 
 The following config options are available: