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

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

dlib/Makefile.am

@@ -4,5 +4,5 @@ AM_CPPFLAGS = \
 noinst_LIBRARIES = libDlib.a
 
 libDlib_a_SOURCES = \
-	dlib.h \
+	dlib.hh \
 	dlib.cc

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.
  */

dlib/dlib.hh

@@ -6,7 +6,8 @@
 #include <stdarg.h>    /* for va_list */
 #include <string.h>    /* for strerror */
 
-#include <stdbool.h>
+#include <string>
+#include <optional>
 
 #include "d_size.h"
 
@@ -184,6 +185,7 @@ void dLib_show_messages(bool show);
  */
 char *dGetcwd(void);
 char *dGethomedir(void);
+std::optional< std::string > dGetline_string(FILE *stream);
 char *dGetline(FILE *stream);
 int dClose(int fd);
 int dUsleep(unsigned long us);