another try at warning suppression

Author: bhaller

gsl/linalg/tridiag.c

@@ -96,8 +96,14 @@ solve_tridiag(
       /* backsubstitution */
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wuninitialized"
+#if defined(__has_warning) && __has_warning("-Wmaybe-uninitialized")
+#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
+#endif
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wuninitialized"
+#if defined(__has_warning) && __has_warning("-Wmaybe-uninitialized")
+#pragma clang diagnostic ignored "-Wmaybe-uninitialized"
+#endif
       x[x_stride * (N - 1)] = c[N - 1];
 #pragma clang diagnostic pop
 #pragma GCC diagnostic pop