adding clang/gcc suppression of the deprecation warnings.

tests/bounds_tests.cpp

@@ -19,7 +19,11 @@
 // so people aren't annoyed by them when running the tool.
 #pragma warning(disable : 26440 26426) // from catch
 #pragma warning(disable : 4996)  // use of function or classes marked [[deprecated]]
+#endif
 
+#if __clang__ || __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
 #endif
 
 #include <catch/catch.hpp> // for AssertionHandler, StringRef, TEST_CASE
@@ -115,3 +119,7 @@ TEST_CASE("bounds_convertible")
 #ifdef CONFIRM_COMPILATION_ERRORS
 copy(src_span_static, dst_span_static);
 #endif
+
+#if __clang__ || __GNUC__
+#pragma GCC diagnostic pop
+#endif