when checking character classes move the utf-8 check in front of all of the other checks; some versions of MSC have a debug mode so if a character isn't either 7-bit ascii or EOF the character class check functions will abort the program. Like, um, yeah, way to creep those standards, people!

mkdio.c

@@ -123,7 +123,7 @@ populate(getc_func getc, void* ctx, mkd_flag_t *flags)
 	    __mkd_enqueue(a, &line);
 	    S(line) = 0;
 	}
-	else if ( isprint(c) || isspace(c) || (c & 0x80) )
+	else if ( (c & 0x80) || isprint(c) || isspace(c) )
 	    EXPAND(line) = c;
     }
 

xml.c

@@ -28,7 +28,7 @@ mkd_xmlchar(unsigned char c)
     case '&':   return "&";
     case '"':   return """;
     case '\'':  return "'";
-    default:    if ( isascii(c) || (c & 0x80) )
+    default:    if ( (c & 0x80) || isascii(c) )
 		    return 0;
 		return "";
     }