* cygprops.h: New file.

	* cygprops.h: New file.
	* dtable.cc (handle_to_fn): Add check for correct installation_key
	string in object name for pipes and ttys.
	* external.cc (cygwin_internal): Add CW_GET_INSTKEY to allow fetching
	the installation_key from cygserver.
	* fhandler_fifo.cc (fhandler_fifo::fifo_name): Add installation_key
	to fifo name.
	* globals.cc: Include cygprops.h.
	(_RDATA): Move slightly and add comment.
	(cygwin_props): Define.
	* mount.cc (mount_info::init): Accommodate the fact that
	installation_root is now a global variable in DLL common shared memory,
	rather than a member of cygwin_shared.
	* pipe.cc (fhandler_pipe::create_selectable): Add installation_key to
	pipe name.
	* shared.cc (installation_root): Define here for storage in DLL
	common shared memory.
	(installation_key): Ditto.
	(installation_key_buf): Ditto.
	(init_installation_root): Convert from shared_info method to ordinary
	function.  Add initializing installation_key.  Invalidate
	installation_key depending of value of disable_key property.  Add
	comment to explain.
	(get_shared_parent_dir): Add installation_key to directory name.
	(get_session_parent_dir): Ditto.
	(shared_info::initialize): Move call to init_installation_root from
	here...
	(memory_init): ...to here.  Add debug output to print installation root
	and installation key.  Add comment to explain why.
	* shared_info.h (SHARED_INFO_CB): Recalculate.
	(CURR_SHARED_MAGIC): Ditto.
	(class shared_info): Remove definition of installation_root and
	declaration of init_installation_root.
	(init_installation_root): Declare.
	(installation_root): Declare.
	(installation_key): Declare.
	* uinfo.cc (pwdgrp::load): Accommodate the fact that installation_root
	is now a global variable in DLL common shared memory.
	* include/cygwin/version.h: Bump API minor number.
	(CYGWIN_INFO_INSTALLATIONS_NAME): Add.
	* include/sys/cygwin.h (cygwin_getinfo_types): Add CW_GET_INSTKEY.