c: Fix C cast error-recovery [PR101171]

c: Fix C cast error-recovery [PR101171]

The following testcase ICEs during error-recovery, as build_c_cast calls
note_integer_operands on error_mark_node and that wraps it into
C_MAYBE_CONST_EXPR which is unexpected and causes ICE later on.
Seems most other callers of note_integer_operands check early if something
is error_mark_node and return before calling note_integer_operands on it.

The following patch fixes it by not calling on error_mark_node, another
possibility would be to handle error_mark_node in note_integer_operands and
just return it.

2021-06-24  Jakub Jelinek  <jakub@redhat.com>

	PR c/101171
	* c-typeck.c (build_c_cast): Don't call note_integer_operands on
	error_mark_node.

	* gcc.dg/pr101171.c: New test.