diff --git a/src/chrono.cpp b/src/chrono.cpp
index 83661b06..45694114 100644
--- a/src/chrono.cpp
+++ b/src/chrono.cpp
@@ -109,10 +109,8 @@ steady_clock::now() _NOEXCEPT
 }
 
 #else  // __APPLE__
-// FIXME: We assume that clock_gettime(CLOCK_MONOTONIC) works on
-// non-apple systems.  Instead, we should check _POSIX_TIMERS and
-// _POSIX_MONOTONIC_CLOCK and fall back to something else if those
-// don't exist.
+// FIXME: if _LIBCPP_HAS_NO_MONOTONIC_CLOCK, then clock_gettime isn't going to
+// work. It may be possible to fall back on something else, depending on the system.
 
 // Warning:  If this is not truly steady, then it is non-conforming.  It is
 //  better for it to not exist and have the rest of libc++ use system_clock