-extern void pp_set_line_maximum_length (pretty_printer *, int);
-extern void pp_set_prefix (pretty_printer *, const char *);
-extern void pp_destroy_prefix (pretty_printer *);
-extern int pp_remaining_character_count_for_line (pretty_printer *);
-extern void pp_clear_output_area (pretty_printer *);
-extern const char *pp_formatted_text (pretty_printer *);
-extern const char *pp_last_position_in_text (const pretty_printer *);
-extern void pp_emit_prefix (pretty_printer *);
-extern void pp_append_text (pretty_printer *, const char *, const char *);
-extern void pp_printf (pretty_printer *, const char *, ...) ATTRIBUTE_PRINTF_2;
-extern void pp_verbatim (pretty_printer *, const char *, ...);
-extern void pp_flush (pretty_printer *);
-extern void pp_format_text (pretty_printer *, text_info *);
-extern void pp_format_verbatim (pretty_printer *, text_info *);
-
+extern void pp_base_set_line_maximum_length (pretty_printer *, int);
+extern void pp_base_set_prefix (pretty_printer *, const char *);
+extern void pp_base_destroy_prefix (pretty_printer *);
+extern int pp_base_remaining_character_count_for_line (pretty_printer *);
+extern void pp_base_clear_output_area (pretty_printer *);
+extern const char *pp_base_formatted_text (pretty_printer *);
+extern const char *pp_base_last_position_in_text (const pretty_printer *);
+extern void pp_base_emit_prefix (pretty_printer *);
+extern void pp_base_append_text (pretty_printer *, const char *, const char *);
+
+/* This header may be included before diagnostics-core.h, hence the duplicate
+ definitions to allow for GCC-specific formats. */
+#if GCC_VERSION >= 3005
+#define ATTRIBUTE_GCC_PPDIAG(m, n) __attribute__ ((__format__ (__gcc_diag__, m ,n))) ATTRIBUTE_NONNULL(m)
+#else
+#define ATTRIBUTE_GCC_PPDIAG(m, n) ATTRIBUTE_NONNULL(m)
+#endif
+extern void pp_printf (pretty_printer *, const char *, ...)
+ ATTRIBUTE_GCC_PPDIAG(2,3);
+
+extern void pp_verbatim (pretty_printer *, const char *, ...)
+ ATTRIBUTE_GCC_PPDIAG(2,3);
+extern void pp_base_flush (pretty_printer *);
+extern void pp_base_format (pretty_printer *, text_info *);
+extern void pp_base_output_formatted_text (pretty_printer *);
+extern void pp_base_format_verbatim (pretty_printer *, text_info *);
+
+extern void pp_base_indent (pretty_printer *);