Add a bit more detail on porechop gcc

Author: cjw85

README.md

@@ -8,10 +8,7 @@ produced in real-time along with fast pipelines for generating draft assemblies.
 
 Documentation can be found at https://nanoporetech.github.io/pomoxis/.
 
-Currently pomoxis supports only unix-like environments. Also of note is that
-the porechop dependency requires a compiler version that may not be installed
-by default on some systems.
-  
+Currently pomoxis supports only unix-like environments. 
 
 Build
 -----
@@ -24,9 +21,15 @@ To setup the environment run:
 
     git clone --recursive https://github.com/nanoporetech/pomoxis
     cd pomoxis
+    # For porechop to be compiled on older systems set these, e.g.:
+    #    export CXX="g++-4.9" CC="gcc-4.9"
     make install
     . ./venv/bin/activate
 
+The installation of porechop (https://github.com/rrwick/Porechop)
+requires a newer compiler than is a available on some systems. It may therefore
+be necessary to install a newer compiler and set variables as in the above.
+
 Running the above within a pre-exisiting virtual environnment may well fail;
 advanced may wish to simply run the `setup.py` file in the standard manner
 after compiling the third party programs as in the `Makefile`.

docs/index.rst

@@ -14,17 +14,23 @@ Installation
 Pomoxis should be installed inside a virtual environment. A Makefile is
 provided to fetch, compile and install all direct dependencies into an
 environment. (Some additional build dependencies are not installed via this
-Makefile, see `.gitlab-ci.yml` for additional requirements if things fail.
+Makefile, see `.travis.yml` for additional requirements if things fail.
 
 To setup the environment run:
 
 .. code-block:: bash
 
-    git clone --recursive https://git/research/pomoxis.git
+    git clone --recursive https://github.com/nanoporetech/pomoxis.git
     cd pomoxis
+    # For porechop to be compiled on older systems set these, e.g.:
+    #    export CXX="g++-4.9" CC="gcc-4.9"
     make install
     . ./venv/bin/activate
 
+The installation of porechop `porechop <https://github.com/rrwick/Porechop>`_
+requires a newer compiler than is a available on some systems. It may therefore
+be necessary to install a newer compiler and set variables as in the above.
+
 See :doc:`examples` for common bundled workflows.
 
 Contents