Rework thread TIB handling & DLL initialization handling

test/test_dll_attach_failure.c

@@ -0,0 +1,17 @@
+#include <windows.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "test_assert.h"
+
+int main(void) {
+    SetLastError(0);
+    HMODULE mod = LoadLibraryA("dll_attach_failure.dll");
+    DWORD error = GetLastError();
+
+    TEST_CHECK_MSG(mod == NULL, "LoadLibraryA unexpectedly succeeded: %p", mod);
+    TEST_CHECK_EQ(ERROR_DLL_INIT_FAILED, error);
+
+    printf("dll_attach_failure: error=%lu\n", (unsigned long)error);
+    return EXIT_SUCCESS;
+}