PR libcc1/113977 points out a case where a simple expression is
rejected with a compiler error message.  The bug here is that gdb does
not inform the plugin of the correct alignment -- in fact, there is no
way to do that.

This patch adds a new method to allow the alignment to be set, and
bumps the C front end protocol version.

It also includes some updates to various comments in 'include', done
here to simplify the merge to binutils-gdb.

include

	* gcc-cp-interface.h (gcc_cp_fe_context_function): Update
	comment.
	* gcc-c-interface.h (enum gcc_c_api_version) <GCC_C_FE_VERSION_2>:
	New constant.
	(gcc_c_fe_context_function): Update comment.
	* gcc-c-fe.def (finish_record_with_alignment): New method.
	Update documentation.

libcc1

	PR libcc1/113977
	* libcc1plugin.cc (plugin_finish_record_or_union): New function.
	(plugin_finish_record_or_union): Rewrite.
	(plugin_init): Use GCC_C_FE_VERSION_2.
	* libcc1.cc (c_vtable): Use GCC_C_FE_VERSION_2.
	(gcc_c_fe_context): Check for GCC_C_FE_VERSION_2.