Only define WXUSINGDLL in DLL configurations when building wxscintilla.

WXUSINGDLL shouldn't be defined in static build configurations, this results
in warnings and might explain errors in MinGW build.

Closes #11966.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65090 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

build/msw/makefile.bcc

@@ -193,8 +193,8 @@ WXEXPAT_OBJECTS =  \
 WXSCINTILLA_CXXFLAGS = $(__RUNTIME_LIBS) -I$(BCCDIR)\include $(__DEBUGINFO) \
 	$(__OPTIMIZEFLAG) $(__THREADSFLAG) -DNDEBUG \
 	-I..\..\src\stc\scintilla\include -I..\..\src\stc\scintilla\src -D__WX__ \
-	-DSCI_LEXER -DLINK_LEXERS -w-8027 -I$(SETUPHDIR) -I..\..\include -DWXUSINGDLL \
-	-D__WXMSW__ $(CPPFLAGS) $(CXXFLAGS)
+	-DSCI_LEXER -DLINK_LEXERS -w-8027 -I$(SETUPHDIR) -I..\..\include \
+	$(__wxscintilla_usingdll_p) -D__WXMSW__ $(CPPFLAGS) $(CXXFLAGS)
 WXSCINTILLA_OBJECTS =  \
 	$(OBJS)\wxscintilla_AutoComplete.obj \
 	$(OBJS)\wxscintilla_CallTip.obj \
@@ -1519,6 +1519,9 @@ __wxjpeg___depname = $(LIBDIRNAME)\wxjpeg$(WXDEBUGFLAG).lib
 !if "$(USE_GUI)" == "1"
 __wxtiff___depname = $(LIBDIRNAME)\wxtiff$(WXDEBUGFLAG).lib
 !endif
+!if "$(SHARED)" == "1"
+__wxscintilla_usingdll_p = -DWXUSINGDLL
+!endif
 !if "$(MONOLITHIC)" == "0"
 EXTRALIBS_FOR_BASE = 
 !endif