PR93685 - ICE in gfc_constructor_append_expr, at fortran/constructor.c:135

PR93685 - ICE in gfc_constructor_append_expr, at fortran/constructor.c:135

Fix handling of F2018 enhancements to DATA statements that allows
initialization of pointer components to derived types, and adjust error
handling for the CHARACTER case.

gcc/fortran/ChangeLog:

	* data.c (gfc_assign_data_value): Restrict use of
	create_character_initializer to constant initializers.
	* trans-expr.c (gfc_conv_initializer): Ensure that character
	initializer is constant, otherwise fall through to get the same
	error handling as for non-character cases.

gcc/testsuite/ChangeLog:

	* gfortran.dg/pr93685_1.f90: New test.
	* gfortran.dg/pr93685_2.f90: New test.