Merge branch 'webrequest-build-fixes' of https://github.com/MaartenBent/wxWidgets

wxWebRequest-related build fixes for MinGW.

See https://github.com/wxWidgets/wxWidgets/pull/2283

samples/webrequest/webrequest.cpp

@@ -10,10 +10,6 @@
 // For compilers that support precompilation, includes "wx/wx.h".
 #include "wx/wxprec.h"
 
-#ifdef __BORLANDC__
-    #pragma hdrstop
-#endif
-
 #ifndef WX_PRECOMP
     #include "wx/wx.h"
 #endif
@@ -29,6 +25,10 @@
     #include "../sample.xpm"
 #endif
 
+#if !wxUSE_WEBREQUEST
+#error "wxUSE_WEBREQUEST must be 1 for this sample."
+#endif
+
 class WebRequestFrame : public wxFrame
 {
 public: