`validation_flush_tests/getcoinscachesizestate` fails on RISCV-64 on master:
```
Running 394 test cases...
test/validation_flush_tests.cpp(99): error: in "validation_flush_tests/getcoinscachesizestate": check chainstate.GetCoinsCacheSizeState(tx_pool, MAX_COINS_CACHE_BYTES, 0) == CoinsCacheSizeState::OK has failed [1 != 0]

*** 1 failure is detected in the test module "Bitcoin Core Test Suite"
```
Haven't investigated why, yet. Apart from the architecture it could also be some dependency version causing the problem (this is a fedora rawhide install with very new versions of everything including gcc and boost).

Edit: see below, this is likely due to a newer `libstdc++`
#include <compat/byteswap.h>
#include <test/util/setup_common.h>
#include <boost/test/unit_test.hpp>
BOOST_FIXTURE_TEST_SUITE(bswap_tests, BasicTestingSetup)
BOOST_AUTO_TEST_CASE(bswap_tests)
{
	
	uint16_t u1 = 0x1234;
	uint32_t u2 = 0x56789abc;
	uint64_t u3 = 0xdef0123456789abc;
	uint16_t e1 = 0x3412;
	uint32_t e2 = 0xbc9a7856;
	uint64_t e3 = 0xbc9a78563412f0de;
	BOOST_CHECK(bswap_16(u1) == e1);
	BOOST_CHECK(bswap_32(u2) == e2);
	BOOST_CHECK(bswap_64(u3) == e3);
}
BOOST_AUTO_TEST_SUITE_END()