feat: adding mcf_length to mp_getmaxvarlengths

BREAKING CHANGE: mp_getmaxvarlengths now returns 0 for non-special missings, and will use numeric length (as opposed to cast-to-character length) by default

fcmp/mcf_string2file.sas

@@ -39,6 +39,9 @@
   @param [out] pkg= (utils) The output package in which to create the function.
     Uses a 3 part format:  libref.catalog.package
 
+  <h4> SAS Macros </h4>
+  @li mf_existfunction.sas
+
 **/
 
 %macro mcf_string2file(wrap=NO
@@ -48,6 +51,8 @@
   ,pkg=UTILS
 )/*/STORE SOURCE*/;
 
+%if %mf_existfunction(mcf_string2file)=1 %then %return;
+
 %if &wrap=YES  %then %do;
   proc fcmp outlib=&lib..&cat..&pkg;
 %end;