glsl: Add a new ir_unop_round_even opcode for GLSL 1.30's roundEven.

Also, update ir_to_mesa's "1.30 is unsupported" case to "handle" it.

src/glsl/ir.cpp

@@ -216,6 +216,7 @@ ir_expression::get_num_operands(ir_expression_operation op)
       1, /* ir_unop_ceil */
       1, /* ir_unop_floor */
       1, /* ir_unop_fract */
+      1, /* ir_unop_round_even */
 
       1, /* ir_unop_sin */
       1, /* ir_unop_cos */
@@ -288,6 +289,7 @@ static const char *const operator_strs[] = {
    "ceil",
    "floor",
    "fract",
+   "round_even",
    "sin",
    "cos",
    "dFdx",

src/glsl/ir.h

@@ -700,6 +700,7 @@ enum ir_expression_operation {
    ir_unop_ceil,
    ir_unop_floor,
    ir_unop_fract,
+   ir_unop_round_even,
    /*@}*/
 
    /**

src/mesa/program/ir_to_mesa.cpp

@@ -1130,6 +1130,7 @@ ir_to_mesa_visitor::visit(ir_expression *ir)
    case ir_binop_bit_and:
    case ir_binop_bit_xor:
    case ir_binop_bit_or:
+   case ir_unop_round_even:
       assert(!"GLSL 1.30 features unsupported");
       break;
    }