* trans-expr.c: Do not include convert.h, ggc.h, real.h, and gimple.h.
	(gfc_conv_string_tmp): Do not assert type comparibilty.
	*  trans-array.c: Do not include gimple.h, ggc.h, and real.h.
	(gfc_conv_expr_descriptor): Remove assert.
	* trans-common.c: Clarify why rtl.h and tm.h are included.
	* trans-openmp.c: Do not include ggc.h and real.h.
	Explain why gimple.h is included.
	* trans-const.c: Do not include ggc.h.
	* trans-stmt.c: Do not include gimple.h, ggc.h, and real.h.
	* trans.c: Do not include ggc.h and real.h.
	Explain why gimple.h is included.
	* trans-types.c: Do not include tm.h.  Explain why langhooks.h
	and dwarf2out.h are included.
	* trans-io.c: Do not include gimple.h and real.h.
	* trans-decl.c: Explain why gimple.h, tm.h, and rtl.h are included.
	* trans-intrinsic.c: Do not include gimple.h.  Explain why tm.h
	is included.

From-SVN: r159640