test: exception: suppress clang warnings

We include the sd_bus header which uses C99 extensions and makes
clang unhappy.  Suppress the extension warning as we have done
in other files.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Icd20825e8123a3860ef5843a76d45da68a2e036c
diff --git a/test/exception/sdbus_error.cpp b/test/exception/sdbus_error.cpp
index 6183d77..94a268d 100644
--- a/test/exception/sdbus_error.cpp
+++ b/test/exception/sdbus_error.cpp
@@ -10,6 +10,11 @@
 
 #include <gtest/gtest.h>
 
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wc99-extensions"
+#endif
+
 // Needed for constructor error testing
 extern sdbusplus::SdBusImpl sdbus_impl;
 
@@ -173,3 +178,7 @@
 }
 
 } // namespace
+
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif