Work around macro symbol conflict with an enum.

This is due to that enum not adhering to the style guide yet:
https://google.github.io/styleguide/cppguide.html#Enumerator_Names

So this needs to be fixed separately, but this is a quick fix.

Signed-off-by: Henner Zeller <[email protected]>

Author: hzeller

src/odb/include/odb/gdsUtil.h

@@ -125,6 +125,8 @@ extern const char* recordNames[];
  */
 enum class DataType : uint8_t
 {
+// TODO: https://google.github.io/styleguide/cppguide.html#Enumerator_Names
+#undef NO_DATA  // avoid conflict with macro in /usr/include/netdb.h
   NO_DATA,
   BIT_ARRAY,
   INT_2,