diff --git a/libcxx/utils/libcxx/test/dsl.py b/libcxx/utils/libcxx/test/dsl.py
--- a/libcxx/utils/libcxx/test/dsl.py
+++ b/libcxx/utils/libcxx/test/dsl.py
@@ -135,9 +135,12 @@
     ])
     return exitCode == 0
 
-def hasLocale(config, locale):
+def hasLocale(config, locale, names):
   """
   Return whether the runtime execution environment supports a given locale.
+  Different systems may use different names for a locale, so this function checks
+  whether any of the passed locale names is supported by setlocale() and returns
+  true if one of them works.
 
   This is done by executing a program that tries to set the given locale using
   %{exec} -- this means that the command may be executed on a remote host
@@ -145,12 +148,20 @@
   """
   program = """
     #include <locale.h>
-    int main(int, char** argv) {
-      if (::setlocale(LC_ALL, argv[1]) != NULL) return 0;
-      else                                      return 1;
+    #include <stdio.h>
+    int main(int argc, char** argv) {
+      // For debugging purposes print which locales are (not) supported.
+      for (int i = 1; i < argc; i++) {
+        if (::setlocale(LC_ALL, argv[i]) != NULL) {
+          printf("%s is supported.\\n", argv[i]);
+          return 0;
+        }
+        printf("%s is not supported.\\n", argv[i]);
+      }
+      return 1;
     }
   """
-  return programOutput(config, program, args=[pipes.quote(locale)],
+  return programOutput(config, program, args=[pipes.quote(l) for l in names],
                        testPrefix="check_locale_" + locale) is not None
 
 def compilerMacros(config, flags=''):
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
@@ -107,7 +107,7 @@
   # Note: Using alts directly in the lambda body here will bind it to the value at the
   # end of the loop. Assigning it to a default argument works around this issue.
   DEFAULT_FEATURES.append(Feature(name='locale.{}'.format(locale),
-                                  when=lambda cfg, alts=alts: any(hasLocale(cfg, alt) for alt in alts)))
+                                  when=lambda cfg, name=locale, alts=alts: hasLocale(cfg, name, alts)))
 
 
 # Add features representing the platform name: darwin, linux, windows, etc...