re PR c++/11131 (Unrelated declaration removes inline flag from function)

	PR c++/11131
	* tree-inline.c (inlinable_function_p): Call the language-specific
	hook early.

	PR c++/11131
	* cp-tree.h (template_for_substitution): Declare.
	* decl2.c (mark_used): Use it when figuring out whether or not a
	function is inline.
	* pt.c (template_for_substitution): Give it external linkage.
	* tree.c (cp_cannot_inline_tree_fn): Instantiate as early as
	possible.

	PR c++/11131
	* g++.dg/opt/template1.C: New test.

From-SVN: r67698