Install wx/osx/carbon/region.h header under OS X

This file was mistakenly removed from the list of wxOSX headers in
602ea92143.

And don't install wx/osx/core/stdpaths.h which doesn't exist any longer (see
abe10b8c00).

Closes #17381.

build/bakefiles/files.bkl

@@ -193,8 +193,8 @@ IMPORTANT: please read docs/tech/tn0016.txt before modifying this file!
     wx/osx/core/evtloop.h
     wx/osx/core/objcid.h
     wx/osx/core/private.h
-    wx/osx/core/stdpaths.h
     wx/osx/core/colour.h
+    wx/osx/carbon/region.h
 </set>
 
 <!-- Base files used by OS X ports (not Carbon) -->

build/files

@@ -139,6 +139,7 @@ BASE_COREFOUNDATION_SRC =
     src/osx/cocoa/utils_base.mm
 
 BASE_COREFOUNDATION_HDR =
+    wx/osx/carbon/region.h
     wx/osx/core/cfdataref.h
     wx/osx/core/cfref.h
     wx/osx/core/cfstring.h
@@ -147,7 +148,6 @@ BASE_COREFOUNDATION_HDR =
     wx/osx/core/evtloop.h
     wx/osx/core/objcid.h
     wx/osx/core/private.h
-    wx/osx/core/stdpaths.h
 
 # Base files used by OS X ports (not Carbon)
 BASE_OSX_SHARED_SRC =