Zig Version

0.15.0-dev.911+31bc6d5a9

Steps to Reproduce and Observed Behavior

Andy has seen flaky failures in the "sigset_t bits" posix test:

expected 1, found 0
1793/2920 posix.test.test.sigset_t bits...FAIL (TestExpectedEqual)
/home/andy/dev/zig/lib/std/testing.zig:109:17: 0x1f34c4d in expectEqualInner__anon_46282 (test)
                return error.TestExpectedEqual;
                ^
/home/andy/dev/zig/lib/std/posix/test.zig:1057:17: 0x2ee9c3f in test.sigset_t bits (test)
                try testing.expectEqual(1, S.handler_called_count);
                ^

The test is "native on my x86_64 host" and "it's rare; I've seen it twice in the last week across hundreds of runs".

Current theories are:

• signal delivery is delayed
• write to S.handler_called_count isn't visible after handler interrupts code
• some other signal handlers (child processes?) are creating conflicts with this test

Expected Behavior

Test is robust and doesn't flake.