Re-factor inclusion of tree.h.

This moves tree.h out of every header. This exposes dependencies of
tree.h in files that should probably not need it after tree and gimple
are separated.

After this change, no header should include tree.h directly. It should
only be included by a .c file. Unfortunately, I did not find an
automatic way of forcing this.

Tested on x86_64 with all languages enabled and using
contrib/config-list.mk.

2013-10-21  Diego Novillo  <dnovillo@google.com>

	* asan.c: Include tree.h
	* bb-reorder.c: Likewise.
	* cfgcleanup.c: Likewise.
	* cfgloopmanip.c: Likewise.
	* data-streamer-in.c: Likewise.
	* data-streamer-out.c: Likewise.
	* data-streamer.c: Likewise.
	* dwarf2cfi.c: Likewise.
	* graphite-blocking.c: Likewise.
	* graphite-clast-to-gimple.c: Likewise.
	* graphite-dependences.c: Likewise.
	* graphite-interchange.c: Likewise.
	* graphite-optimize-isl.c: Likewise.
	* graphite-poly.c: Likewise.
	* graphite-scop-detection.c: Likewise.
	* graphite-sese-to-poly.c: Likewise.
	* graphite.c: Likewise.
	* ipa-devirt.c: Likewise.
	* ipa-profile.c: Likewise.
	* ipa.c: Likewise.
	* ira.c: Likewise.
	* loop-init.c: Likewise.
	* loop-unroll.c: Likewise.
	* lower-subreg.c: Likewise.
	* lto/lto-object.c: Likewise.
	* recog.c: Likewise.
	* reginfo.c: Likewise.
	* tree-loop-distribution.c: Likewise.
	* tree-parloops.c: Likewise.
	* tree-ssa-strlen.c: Likewise.
	* tree-streamer.c: Likewise.
	* value-prof.c: Likewise.
	* target-globals.c: Likewise.
	* expr.h: Include tree-core.h instead of tree.h.
	* gimple.h: Likewise.
	* ipa-prop.h: Likewise.
	* ipa-utils.h: Likewise.
	* lto-streamer.h: Likewise.
	* streamer-hooks.h: Likewise.
	* ipa-reference.h: Include cgraph.h instead of tree.h.
	* cgraph.h: Include basic-block.h instead of tree.h.
	* tree-streamer.h: Do not include tree.h.
	* genattrtab.c (write_header): Generate inclusion of
	tree.h.
	* genautomata.c (main): Likewise.
	* genemit.c: Likewise.
	* genopinit.c: Likewise.
	* genoutput.c (output_prologue): Likewise.
	* genpeep.c: Likewise.

testsuite/ChangeLog

	* g++.dg/plugin/selfassign.c: Include tree.h.
	* gcc.dg/plugin/finish_unit_plugin.c: Likewise.
	* gcc.dg/plugin/ggcplug.c: Likewise.
	* gcc.dg/plugin/one_time_plugin.c: Likewise.
	* gcc.dg/plugin/selfassign.c: Likewise.
	* gcc.dg/plugin/start_unit_plugin.c: Likewise.

From-SVN: r203908