Since the kind of the hidden character length variable is not part of
the character variable definition, we must ensure that character
lengths are always of the same kind in interfaces, regardless of how
they were declared in the source. This patch ensures this when calling
a procedure.

Regtested on x86_64-pc-linux-gnu and i686-pc-linux-gnu.

gcc/fortran/ChangeLog:

2018-03-21  Janne Blomqvist  <jb@gcc.gnu.org>

	PR fortran/84615
	* trans-expr.c (gfc_conv_procedure_call): Convert charlen to
	gfc_charlen_type_node when calling procedure.

gcc/testsuite/ChangeLog:

2018-03-21  Janne Blomqvist  <jb@gcc.gnu.org>

	PR fortran/84615
	* gfortran.dg/char_result_17.f90: New test.

From-SVN: r258736