options/posix: Fix gettid() signature

options/posix/generic/unistd-stubs.cpp

@@ -287,7 +287,7 @@ int getpagesize(void) {
 // usleep() is provided by the platform
 
 // This is a Linux extension
-pid_t gettid(void *, size_t, unsigned int) {
+pid_t gettid(void) {
 	__ensure(!"Not implemented");
 	__builtin_unreachable();
 }