feat: creating new mx_ suite of macros!

also adding new mx_getcode macro

tests/base/mp_abort.test.nofix.sas

@@ -0,0 +1,36 @@
+/**
+  @file
+  @brief Testing mp_abort macro
+  @details This is an unfixed problem with mp_abort when using the
+  'unclosed macro' technique.  This is only relevant for 9.4m3 environments,
+  which can suffer from hung multibridge sessions from %abort and endsas.
+
+  The issue is that when called within a macro, within a %include, AND that
+  macro contains subsequent logic, the service does not end cleanly - rather,
+  we see:
+
+      ERROR: %EVAL function has no expression to evaluate, or %IF statement has no condition.
+      ERROR: The macro TEST will stop executing.
+
+  We are not able to test this without a 9.4m3 environment, it is marked as
+  nofix.
+
+  <h4> SAS Macros </h4>
+  @li mp_abort.sas
+  @li mp_assert.sas
+
+**/
+
+%macro test();
+
+filename blah temp;
+data _null_;
+  file blah;
+  put '%mp_abort();';
+run;
+%inc blah;
+
+%if 1=1 %then %put Houston - we have a problem here;
+%mend test;
+
+%test()