Added -Wzero-as-null-pointer-constant, replaced NULL --> UAVCAN_NULLPTR. All changes are automatic, no manual edits to the library code.

libuavcan/test/util/map.cpp

@@ -5,6 +5,7 @@
 #if __GNUC__
 // We need auto_ptr for compatibility reasons
 # pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+# pragma GCC diagnostic ignored "-Wzero-as-null-pointer-constant"
 #endif
 
 #include <string>
@@ -139,7 +140,7 @@ TEST(Map, Basic)
         const std::string key   = toString(i);
         const std::string value = toString(i);
         std::string* res = map->insert(key, value);  // Will override some from the above
-        if (res == NULL)
+        if (res == UAVCAN_NULLPTR)
         {
             ASSERT_LT(2, i);
             break;