this is mildly ugly, but less ugly than gnulib trying to poke at the
definition of the FILE structure...
--- /dev/null
+#include "stdio_impl.h"
+
+size_t __freadahead(FILE *f)
+{
+ return f->rend - f->rpos;
+}
+
+const char *__freadptr(FILE *f, size_t *sizep)
+{
+ size_t size = f->rend - f->rpos;
+ if (!size) return 0;
+ *sizep = size;
+ return f->rpos;
+}
+
+void __freadptrinc(FILE *f, size_t inc)
+{
+ f->rpos += inc;
+}
+
+void __fseterr(FILE *f)
+{
+ f->flags |= F_ERR;
+}