Ifdef maze in comm.h causes problems with extern "C".

This straightens that out.  (`COMM_INTERNAL` needs to be
respected.)

sc2/src/uqm/comm.h

@@ -103,6 +103,14 @@ signaledStopTalkingAnim (void)
 	return CommData.AlienTalkDesc.AnimFlags & TALK_DONE;
 }
 
+#if defined(__cplusplus)
+}
+#endif
+
+#endif // defined(COMM_INTERNAL)
+
+#if defined(__cplusplus)
+extern "C" {
 #endif
 
 #define TEXT_X_OFFS 1