Don't include the manifest in wx/msw/wx.rc by default for MSVC compiler.

The later versions of this compiler don't need it any more, so make it easier
to set up the projects for them at the expense of MSVC 6 and 7 users who will
now need to explicitly define wxUSE_RC_MANIFEST=1 and predefine the
architecture macro (or setup their resource compiler include path to get
wx/msw/rcdefs.h under the lib directory but predefining the architecture is
clearly simpler).

Do generate manifest when using gcc as it predefines the architecture macros
allowing us to avoid requiring using the generated rcdefs.h.

The other compilers will be dealt with as needed if anybody is still using
them.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73483 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -496,6 +496,11 @@ Build system changes
   configurations if you need them is to use nmake from the command line with
   WXUNIV=1 or UNICODE=0 command line parameter respectively.
 
+- The manifest is not included by wx/msw/wx.rc any longer for MSVC compiler.
+  If you're using MSVC 6 or 7 which require it, you must explicitly define
+  wxUSE_RC_MANIFEST=1 and also predefine WX_CPU_X86 in the resource compiler
+  options in your project file.
+
 
 Major new features in this release
 ----------------------------------