Merge pull request #31 from su2code/feature_python_version

Updated required python version

Author: talbring

_docs_v7/Build-SU2-Linux-MacOS.md

@@ -80,12 +80,12 @@ If you want to use the python wrapper capabilities, also `swig` and `mpi4py` are
 
 On **Mac OS X**, you can use the [Homebrew](http://brew.sh/) package manager. Once it is installed on your system, you can install Swig by running:
 
-    $ sudo brew install swig
+    $ brew install swig
 
 Install mpi4py with Python pip using easy install:
 
-    $ sudo easy_install pip
-    $ sudo pip install mpi4py
+    $ easy_install pip
+    $ pip install mpi4py
 
 ---
 
@@ -198,4 +198,9 @@ Meson looks for an MPI installation using [pkg-config](https://en.wikipedia.org/
 ### mpi4py library is not found ###
 Meson imports the mpi4py module and searches for the include path. If it is installed in a custom location, make sure to add this path to the `PYTHONPATH` environment variable prior calling `meson.py`.
 
-
+### Ninja compiles but fails to install ###
+If building on a cluster that uses a NFS filesystem, ninja may finish the compilation but fail to install with an error such as:
+```
+OSError: [Errno 22] Invalid argument: 'SU2_CFD/src/SU2_CFD'
+```
+This is a known bug in earlier versions of Python 3. Try upgrading to Python >= 3.7 then rerun ninja.