instructions for new gcc versions

doc/compile_Linux.md

@@ -97,6 +97,13 @@
 - g++ version 5.1 or higher is required for full C++11 support. 
 If you want to compile the binary without installing libraries / compiler or just compile binary for some other distribution, please check the [build_xmr-stak_docker.sh script](scripts/build_xmr-stak_docker/build_xmr-stak_docker.sh).
 
+- Some newer gcc versions are not supported by CUDA (e.g. Ubuntu 17.10). It will require installing gcc 5 but you can avoid changing defaults.
+
+In that case you can force CUDA to use an older compiler in the following way:
+```
+cmake -DCUDA_HOST_COMPILER=/usr/bin/gcc-5 ..
+```
+
 ### To do a generic and static build for a system without gcc 5.1+
 ```
     cmake -DCMAKE_LINK_STATIC=ON -DXMR-STAK_COMPILE=generic .