DOC: Modules without a src/ directory should not set ENABLE_SHARED

Change-Id: I5abbc950aae500fde44cc481c96e5443501dbda5

Author: thewtex

SoftwareGuide/Latex/DG04-CreateAModule.tex

@@ -250,6 +250,10 @@ \section{Libraries}
 ...
 \end{minted}
 
+Modules that do not build a library in their \texttt{src} directory or do not
+have export specifications on their class declarations should not set
+\code{ENABLE\_SHARED}.
+
 
 \section{Tests}
 \label{sec:Tests}