Improved support for Makefiles that need to recurse in subdirectories.

include/Makefile.in

diff --git a/include/Makefile.in b/include/Makefile.in
index 5fda48d..f20a2ca 100644
--- a/include/Makefile.in
+++ b/include/Makefile.in
@@ -10,6 +10,8 @@
 	wingdi.h \
 	winuser.h
 
+EXTRASUBDIRS = bitmaps wine
+
 @MAKE_RULES@
 
 install::