Rule 21.1: Make compiler compatibile

Compliers already exclude the #define defined case.

Author: lcartey

c/misra/test/rules/RULE-21-1/DefineAndUndefUsedOnReservedIdentifierOrMacroName.expected

@@ -1,4 +1,3 @@
 | test.c:1:1:1:17 | #define _NOT_OKAY | Reserved identifier '_NOT_OKAY' has been undefined or redefined. |
 | test.c:2:1:2:16 | #undef _NOT_OKAY | Reserved identifier '_NOT_OKAY' has been undefined or redefined. |
-| test.c:4:1:4:15 | #define defined | Reserved identifier 'defined' has been undefined or redefined. |
 | test.c:5:1:5:13 | #define errno | Reserved identifier 'errno' has been undefined or redefined. |

c/misra/test/rules/RULE-21-1/test.c

@@ -1,7 +1,7 @@
 #define _NOT_OKAY // NON_COMPLIANT
 #undef _NOT_OKAY  // NON_COMPLIANT
 
-#define defined // NON_COMPLIANT
-#define errno   // NON_COMPLIANT
+// #define defined // NON_COMPILABLE
+#define errno // NON_COMPLIANT
 
 #define NDEBUG 1 // COMPLIANT