Make sure our language definitions for listings are actually being used

While this wasn't a problem for our 'FORTRAN77', our definition of 'C' was actually completely ignored in favor of some predefined dialect of C.

mlsshared.sty

@@ -99,7 +99,7 @@
 }[keywords,comments,strings]
 
 % Duplicate this definition here to avoid issue
-\lstdefinelanguage{FORTRAN77}{%
+\lstdefinelanguage{FORTRAN77}{% Define custom language to avoid collision with predefined [77]Fortran.
     basicstyle=\upshape\smallifpdf\ttfamily, % size of fonts used for the code
     morekeywords={%
         ASSIGN,BACKSPACE,CALL,CHARACTER,%
@@ -128,7 +128,7 @@
     morestring=[d]'
 }[keywords,comments,strings]
 
-\lstdefinelanguage{C}{%
+\lstdefinelanguage[MLS]{C}{% Define new dialect to avoid collision with predefined dialects of C.
     basicstyle=\upshape\smallifpdf\ttfamily, % size of fonts used for the code
     morekeywords={%
         auto,break,case,char,const,continue,default,do,double,%
@@ -165,6 +165,7 @@
   showstringspaces=false,
   frame=lrtb,
   belowskip=0pt,
+  defaultdialect=[MLS]C,
 }
 
 % Misc math