diff --git a/build/bakefiles/wx.bkl b/build/bakefiles/wx.bkl
index 9c7b419b40..fe5f922871 100644
--- a/build/bakefiles/wx.bkl
+++ b/build/bakefiles/wx.bkl
@@ -205,7 +205,7 @@
             <depends-on-file>$(SRCDIR)/include/wx/msw/genrcdefs.h</depends-on-file>
 
             <command>
-                $(DOLLAR)(CPP) "$(nativePaths(SRCDIR))\include\wx\msw\genrcdefs.h" > "$(SETUPHDIR)\wx\msw\rcdefs.h"
+                $(DOLLAR)(CPP) $(DOLLAR)(CPPFLAGS) "$(nativePaths(SRCDIR))\include\wx\msw\genrcdefs.h" > "$(SETUPHDIR)\wx\msw\rcdefs.h"
             </command>
 
         </action>
diff --git a/build/msw/makefile.bcc b/build/msw/makefile.bcc
index fefb2ee256..a7690d7647 100644
--- a/build/msw/makefile.bcc
+++ b/build/msw/makefile.bcc
@@ -5580,7 +5580,7 @@ $(SETUPHDIR)\wx\msw: $(SETUPHDIR)\wx
 	if not exist $(SETUPHDIR)\wx\msw mkdir $(SETUPHDIR)\wx\msw
 
 $(SETUPHDIR)\wx\msw\rcdefs.h: $(SETUPHDIR)\wx\msw ..\..\include\wx\msw\genrcdefs.h
-	$(CPP) "..\..\include\wx\msw\genrcdefs.h" > "$(SETUPHDIR)\wx\msw\rcdefs.h"
+	$(CPP) $(CPPFLAGS) "..\..\include\wx\msw\genrcdefs.h" > "$(SETUPHDIR)\wx\msw\rcdefs.h"
 
 build_cfg_file: $(SETUPHDIR)
 	@echo WXVER_MAJOR=3 >$(BUILD_CFG_FILE)
diff --git a/build/msw/makefile.gcc b/build/msw/makefile.gcc
index c1c27dcc5f..908cae4338 100644
--- a/build/msw/makefile.gcc
+++ b/build/msw/makefile.gcc
@@ -5885,7 +5885,7 @@ $(SETUPHDIR)\wx\msw: $(SETUPHDIR)\wx
 	if not exist $(SETUPHDIR)\wx\msw mkdir $(SETUPHDIR)\wx\msw
 
 $(SETUPHDIR)\wx\msw\rcdefs.h: $(SETUPHDIR)\wx\msw ..\..\include\wx\msw\genrcdefs.h
-	$(CPP) "..\..\include\wx\msw\genrcdefs.h" > "$(SETUPHDIR)\wx\msw\rcdefs.h"
+	$(CPP) $(CPPFLAGS) "..\..\include\wx\msw\genrcdefs.h" > "$(SETUPHDIR)\wx\msw\rcdefs.h"
 
 build_cfg_file: $(SETUPHDIR)
 	@echo WXVER_MAJOR=3 >$(BUILD_CFG_FILE)
diff --git a/build/msw/makefile.vc b/build/msw/makefile.vc
index 8f828728ba..c679224f48 100644
--- a/build/msw/makefile.vc
+++ b/build/msw/makefile.vc
@@ -6331,7 +6331,7 @@ $(SETUPHDIR)\wx\msw: $(SETUPHDIR)\wx
 	if not exist $(SETUPHDIR)\wx\msw mkdir $(SETUPHDIR)\wx\msw
 
 $(SETUPHDIR)\wx\msw\rcdefs.h: $(SETUPHDIR)\wx\msw ..\..\include\wx\msw\genrcdefs.h
-	$(CPP) "..\..\include\wx\msw\genrcdefs.h" > "$(SETUPHDIR)\wx\msw\rcdefs.h"
+	$(CPP) $(CPPFLAGS) "..\..\include\wx\msw\genrcdefs.h" > "$(SETUPHDIR)\wx\msw\rcdefs.h"
 
 build_cfg_file: $(SETUPHDIR)
 	@echo WXVER_MAJOR=3 >$(BUILD_CFG_FILE)