AC_FUNC_MMAP
AC_FUNC_FSEEKO
AC_CHECK_FUNCS(strptime timegm snprintf vsnprintf vasprintf drand48)
-AC_CHECK_FUNCS(strtoll strtoimax usleep ftello sigblock sigsetjmp)
+AC_CHECK_FUNCS(strtoll strtoimax usleep ftello sigblock sigsetjmp memrchr)
dnl We expect to have these functions on Unix-like systems configure
dnl runs on. The defines are provided to get them in config.h.in so