From /usr/include/stdio.h:
/*
* Routines in POSIX 1003.1:200x.
*/
#ifndef __STRICT_ANSI__
# ifndef _REENT_ONLY
# ifndef dprintf
int _EXFUN(dprintf, (int, const char *__restrict, ...)
_ATTRIBUTE ((__format__ (__printf__, 2, 3))));
# endif
FILE * _EXFUN(fmemopen, (void *__restrict, size_t, const char *__restrict));
/* getdelim - see __getdelim for now */
/* getline - see __getline for now */
FILE * _EXFUN(open_memstream, (char **, size_t *));
#if __BSD_VISIBLE || __POSIX_VISIBLE >= 200809
int _EXFUN(renameat, (int, const char *, int, const char *));
#endif
int _EXFUN(vdprintf, (int, const char *__restrict, __VALIST)
_ATTRIBUTE ((__format__ (__printf__, 2, 0))));
# endif
#endif
so it's not like it's not there. I think the makefile might be misconfigured.