bootstrap: Fix building with GCC 4.2 [PR89494]

bootstrap: Fix building with GCC 4.2 [PR89494]

GCC 4.2 (but I think not the latest tip of GCC 4.2 branch) has broken value
initialization, see PR33916.  The following patch provides a workaround for
that.  Tested with GCC 4.2 on a reduced testcase I've distilled from the
assign_param_data_one class which has been miscompiled the same.

2020-04-16  Jakub Jelinek  <jakub@redhat.com>

	PR bootstrap/89494
	* function.c (assign_parm_find_data_types): Add workaround for
	BROKEN_VALUE_INITIALIZATION compilers.