Add note about C extensions

There was some confusion regarding the output of easy_install pyramid
when the Python header files were not installed, these errors are
harmless however adding a simple note would have stopped a lot of
frustration.

1 files changed, 11 insertions, 0 deletions

diff --git a/docs/narr/install.rst b/docs/narr/install.rst
index fb67b899b..6260c36f2 100644
--- a/docs/narr/install.rst
+++ b/docs/narr/install.rst
@@ -25,6 +25,10 @@ on :term:`PyPy` (1.9+).
 :app:`Pyramid` installation does not require the compilation of any C code, so
 you need only a Python interpreter that meets the requirements mentioned.
 
+Certain :app:`Pyramid` dependencies can optionally use C Python extensions,
+if a compiler or Python headers are unavailable the dependency will fall back
+to using pure Python instead.
+
 For Mac OS X Users
 ~~~~~~~~~~~~~~~~~~
 
@@ -292,6 +296,13 @@ itself using the following commands:
 The ``easy_install`` command will take longer than the previous ones to
 complete, as it downloads and installs a number of dependencies.
 
+.. note::
+
+   If you see any errors related to failing to compile the C extensions, you
+   may safely ignore those errors. If you wish to use the C extensions, please
+   verify that you have a functioning compiler and the Python header files
+   installed.
+
 .. index::
    single: installing on Windows