random: Dynamically calculate the state size when seeding with CSPRNG

Instead of hardcoding struct names, or even sizes, we can just determine the
actual size of the target structure using sizeof().

Author: TimWolla

ext/random/engine_pcgoneseq128xslrr64.c

@@ -153,7 +153,7 @@ PHP_METHOD(Random_Engine_PcgOneseq128XslRr64, __construct)
 	ZEND_PARSE_PARAMETERS_END();
 
 	if (seed_is_null) {
-		if (php_random_bytes_throw(&state->state, sizeof(php_random_uint128_t)) == FAILURE) {
+		if (php_random_bytes_throw(&state->state, sizeof(state->state)) == FAILURE) {
 			zend_throw_exception(random_ce_Random_RandomException, "Failed to generate a random seed", 0);
 			RETURN_THROWS();
 		}

ext/random/engine_xoshiro256starstar.c

@@ -213,7 +213,7 @@ PHP_METHOD(Random_Engine_Xoshiro256StarStar, __construct)
 
 	if (seed_is_null) {
 		do {
-			if (php_random_bytes_throw(&state->state, 32) == FAILURE) {
+			if (php_random_bytes_throw(&state->state, sizeof(state->state)) == FAILURE) {
 				zend_throw_exception(random_ce_Random_RandomException, "Failed to generate a random seed", 0);
 				RETURN_THROWS();
 			}