ifndef some macros to allow overriding during compilation or be able to get some warnings during redefinition

features/frameworks/greentea-client/greentea-client/test_env.h

@@ -33,8 +33,12 @@
 /**
  *  Auxilary macros
  */
+#ifndef NL
 #define NL "\n"
+#endif
+#ifndef RCNL
 #define RCNL "\r\n"
+#endif
 
 /**
  *  Auxilary macros to keep mbed-drivers compatibility with utest before greentea-client

features/unsupported/tests/mbed/env/test_env.h

@@ -4,8 +4,12 @@
 #include <stdio.h>
 #include "mbed.h"
 
+#ifndef NL
 #define NL "\n"
+#endif
+#ifndef RCNL
 #define RCNL "\r\n"
+#endif
 
 // Const strings used in test_end
 extern const char* TEST_ENV_START;