diff --git a/libcxx/utils/libcxx/test/features.py b/libcxx/utils/libcxx/test/features.py
--- a/libcxx/utils/libcxx/test/features.py
+++ b/libcxx/utils/libcxx/test/features.py
@@ -149,6 +149,14 @@
   Feature(name='freebsd', when=lambda cfg: '__FreeBSD__' in compilerMacros(cfg))
 ]
 
+# Add features representing the build host platform name.
+# The build host could differ from the target platform for cross-compilation.
+DEFAULT_FEATURES += [
+  Feature(name='buildhost={}'.format(sys.platform.lower().strip())),
+  # sys.platform can be represented by "sub-system" on Windows host, such as 'win32', 'cygwin', 'mingw' & etc.
+  # Here is a consolidated feature for the build host plaform name on Windows.
+  Feature(name='buildhost=windows', when=lambda cfg: platform.system().lower().startswith('windows'))
+]
 
 # Detect whether GDB is on the system, and if so add a substitution to access it.
 DEFAULT_FEATURES += [