diff --git a/libcxx/test/std/language.support/support.runtime/ctime.timespec.compile.pass.cpp b/libcxx/test/std/language.support/support.runtime/ctime.timespec.compile.pass.cpp
--- a/libcxx/test/std/language.support/support.runtime/ctime.timespec.compile.pass.cpp
+++ b/libcxx/test/std/language.support/support.runtime/ctime.timespec.compile.pass.cpp
@@ -15,8 +15,11 @@
 // unavailable until macOS 10.15
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14}}
 
-// MinGW lacks timespec_get.
-// XFAIL: target={{.+}}-windows-gnu
+// MinGW used to lack timespec_get, but has got it in newer versions.
+// Mark the test as unsupported for a transition period, to avoid spurious
+// failures when upgrading the precommit testing environment. After
+// the testing environment is upgraded, we could remove the marking altogether.
+// UNSUPPORTED: target={{.+}}-windows-gnu
 
 #include <ctime>
 #include <type_traits>