make wxSetEnv compatible with ANSI and Unicode, deprecate passing NULL to it in favour of wxUnsetEnv()

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@46547 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/latex/wx/function.tex

@@ -4686,13 +4686,17 @@ Returns \true if the variable exists, \false otherwise.
 
 \membersection{wxSetEnv}\label{wxsetenv}
 
-\func{bool}{wxSetEnv}{\param{const wxString\&}{ var}, \param{const wxChar *}{value}}
+\func{bool}{wxSetEnv}{\param{const wxString\&}{ var}, \param{const wxString\& }{value}}
 
 Sets the value of the environment variable {\it var} (adding it if necessary)
 to {\it value}.
 
 Returns \true on success.
 
+\wxheading{See also}
+
+\helpref{wxUnsetEnv}{wxunsetenv}
+
 
 \membersection{wxUnsetEnv}\label{wxunsetenv}
 
@@ -4703,3 +4707,7 @@ Removes the variable {\it var} from the environment.
 function.
 
 Returns \true on success.
+
+\wxheading{See also}
+
+\helpref{wxSetEnv}{wxsetenv}