Added pstore.h and an IDL file to generate it.

diff --git a/include/Makefile.in b/include/Makefile.in
index fa57b08..8d6b945 100644
--- a/include/Makefile.in
+++ b/include/Makefile.in
@@ -17,6 +17,7 @@
 	objidl.idl \
 	ocidl.idl \
 	oleidl.idl \
+	pstore.idl \
 	servprov.idl \
 	shldisp.idl \
 	shobjidl.idl \