libstdc++: Fix unused warning for new variable

This newly-introduced variable isn't used on all paths, so add the
[[maybe_unused]] attribute.

libstdc++-v3/ChangeLog:

	* src/c++11/random.cc (random_device::_M_init): Add maybe_unused
	attribute.

diff --git a/libstdc++-v3/src/c++11/random.cc b/libstdc++-v3/src/c++11/random.cc
index cece6edbfc720124f5646f41b87b58616f91e763..75989bd33375800d04a5ca5788f99c103c199ea2 100644 (file)
--- a/libstdc++-v3/src/c++11/random.cc
+++ b/libstdc++-v3/src/c++11/random.cc
@@ -374,11 +374,11 @@ namespace std _GLIBCXX_VISIBILITY(default)
                                      " unsupported token"));
 
 #if defined ENOSYS
-    const int unsupported = ENOSYS;
+    [[maybe_unused]] const int unsupported = ENOSYS;
 #elif defined ENOTSUP
-    const int unsupported = ENOTSUP;
+    [[maybe_unused]] const int unsupported = ENOTSUP;
 #else
-    const int unsupported = 0;
+    [[maybe_unused]] const int unsupported = 0;
 #endif
     int err = 0;