+\twocolitem{WX\_PRECOMP}{is defined if precompiled headers (PCH) are in use. In
+this case, \texttt{wx/wxprec.h} includes \texttt{wx/wx.h} which, in turn,
+includes a number of wxWidgets headers thus making it unnecessary to include
+them explicitly. However if this is not defined, you do need to include them
+and so the usual idiom which allows to support both cases is to first include
+\texttt{wx/wxprec.h} and then, inside \texttt{#ifndef WX\_PRECOMP}, individual
+headers you need.}
+\twocolitem{\_UNICODE and UNICODE}{both are defined if wxUSE\_UNICODE is set to $1$}
+\twocolitem{wxUSE\_GUI}{this particular feature test macro is defined to $1$
+when compiling or using the library with the GUI features activated, if it is
+defined as $0$, only wxBase is available.}
+\twocolitem{wxUSE\_BASE}{only used by wxWidgets internally (defined as $1$ when
+building wxBase code, either as a standalone library or as part of the
+monolithic wxWidgets library, defined as $0$ when building GUI library only)}
+\twocolitem{wxNO\_RTTI}{is defined if the compiler RTTI support has been switched off}
+\twocolitem{wxNO\_EXCEPTIONS}{is defined if the compiler support for C++
+exceptions has been switched off}
+\twocolitem{wxNO\_THREADS}{if this macro is defined, the compilation options
+don't include compiler flags needed for multithreaded code generation. This
+implies that wxUSE\_THREADS is $0$ and also that other (non wx-based) threading
+packages cannot be used neither.}