Get some of the last remaining C files into C++

They still need to be fixed up, but they now build with C++.

dlib/dlib.cc

@@ -27,7 +27,7 @@
 #include <ctype.h>
 #include <time.h>
 
-#include "dlib.h"
+#include "dlib.hh"
 
 static bool dLib_show_msg = TRUE;
 
@@ -962,6 +962,27 @@ char *dGetline (FILE *stream)
    return line;
 }
 
+std::optional< std::string >
+dGetline_string (FILE *stream)
+{
+   int ch;
+   Dstr *dstr;
+
+   if( stream == nullptr ) return std::nullopt;
+
+   dstr = dStr_sized_new(64);
+   while ((ch = fgetc(stream)) != EOF) {
+      dStr_append_c(dstr, ch);
+      if (ch == '\n')
+         break;
+   }
+
+   std::optional< std::string > line;
+   if(dstr->len) line= dstr->str;
+   dStr_free(dstr, 1);
+   return line;
+}
+
 /**
  * Close a FD handling EINTR.
  */