-XBT_PUBLIC(int) asprintf (char **ptr, const char *fmt, /*args*/ ...) _XBT_GNUC_PRINTF(2,3);
-XBT_PUBLIC(int) vasprintf (char **ptr, const char *fmt, va_list ap);
-XBT_PUBLIC(char*) bprintf (const char*fmt, ...) _XBT_GNUC_PRINTF(1,2);
+#ifndef __USE_GNU /* do not redeclare existing headers */
+XBT_PUBLIC(int) asprintf(char **ptr, const char *fmt, /*args */
+ ...) _XBT_GNUC_PRINTF(2, 3);
+XBT_PUBLIC(int) vasprintf(char **ptr, const char *fmt, va_list ap);
+#endif
+XBT_PUBLIC(char *) bprintf(const char *fmt, ...) _XBT_GNUC_PRINTF(1, 2);