executor: fix compiler warnings in 32-bit mode

executor/executor.cc: In function ‘uint64 read_input(uint8**, bool)’:
executor/executor.cc:1487:59: error: format ‘%zu’ expects argument of type
                              ‘size_t’, but argument 3 has type ‘int’
			      [-Werror=format=]
executor/executor.cc:1495:67: error: format ‘%zu’ expects argument of type
                                     ‘size_t’, but argument 3 has type ‘int’
				     [-Werror=format=]

Signed-off-by: Alexander Egorenkov <eaibmz@gmail.com>

executor/executor.cc

@@ -1484,15 +1484,15 @@ uint64 read_input(uint8** input_posp, bool peek)
 	for (int i = 0;; i++, shift += 7) {
 		const int maxLen = 10;
 		if (i == maxLen)
-			failmsg("varint overflow", "pos=%zu", *input_posp - input_data);
+			failmsg("varint overflow", "pos=%zu", (size_t)(*input_posp - input_data));
 		if (input_pos >= input_data + kMaxInput)
 			failmsg("input command overflows input", "pos=%p: [%p:%p)",
 				input_pos, input_data, input_data + kMaxInput);
 		uint8 b = *input_pos++;
 		v |= uint64(b & 0x7f) << shift;
 		if (b < 0x80) {
 			if (i == maxLen - 1 && b > 1)
-				failmsg("varint overflow", "pos=%zu", *input_posp - input_data);
+				failmsg("varint overflow", "pos=%zu", (size_t)(*input_posp - input_data));
 			break;
 		}
 	}