* include/subauth.h: Ditto.
* include/ipexport.h: Fix global header define not to contain
trailing underscore. Change layout according to standard.
* include/iphlpapi.h: Ditto.
* include/ipifcons.h: Ditto.
* include/iptypes.h: Ditto.
* include/ntdef.h: Ditto. Define conditional datatypes dependent
of inclusion of ntdecapi.h and subauth.h.
* lib/secur32.def: New stub for secur32.dll.
