diff --git a/include/ChangeLog b/include/ChangeLog
index c99733eb9..c80aeb8a5 100644
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,3 +1,9 @@
+2011-07-01  Joel Brobecker  <brobecker@adacore.com>
+
+	* filenames.h (HAVE_CASE_INSENSITIVE_FILE_SYSTEM): Define
+	on Darwin, as well as on the systems that use a DOS-like
+	filesystem.
+
 2011-06-22  Jakub Jelinek  <jakub@redhat.com>
 
 	PR debug/47858
diff --git a/include/filenames.h b/include/filenames.h
index d4955df66..75ec3302d 100644
--- a/include/filenames.h
+++ b/include/filenames.h
@@ -34,10 +34,18 @@ extern "C" {
 #  ifndef HAVE_DOS_BASED_FILE_SYSTEM
 #    define HAVE_DOS_BASED_FILE_SYSTEM 1
 #  endif
+#  ifndef HAVE_CASE_INSENSITIVE_FILE_SYSTEM
+#    define HAVE_CASE_INSENSITIVE_FILE_SYSTEM 1
+#  endif
 #  define HAS_DRIVE_SPEC(f) HAS_DOS_DRIVE_SPEC (f)
 #  define IS_DIR_SEPARATOR(c) IS_DOS_DIR_SEPARATOR (c)
 #  define IS_ABSOLUTE_PATH(f) IS_DOS_ABSOLUTE_PATH (f)
 #else /* not DOSish */
+#  if defined(__APPLE__)
+#    ifndef HAVE_CASE_INSENSITIVE_FILE_SYSTEM
+#      define HAVE_CASE_INSENSITIVE_FILE_SYSTEM 1
+#    endif
+#  endif /* __APPLE__ */
 #  define HAS_DRIVE_SPEC(f) (0)
 #  define IS_DIR_SEPARATOR(c) IS_UNIX_DIR_SEPARATOR (c)
 #  define IS_ABSOLUTE_PATH(f) IS_UNIX_ABSOLUTE_PATH (f)