./configure 不懂?

[weixin_38054840]

在安装zlib时做./configure时出现下类出错信息,请问这是什么问题啊
root# ./configure   
Checking for gcc...
Building static library libz.a version 1.2.1 with cc.
Checking for unistd.h... No.
Checking whether to use vs[n]printf() or s[n]printf()... using s[n]printf()
Checking for snprintf() in stdio.h... No.
  WARNING: snprintf() not found, falling back to sprintf(). zlib
  can build but will be open to possible buffer-overflow security
  vulnerabilities.
Checking for return value of sprintf()... No.
  WARNING: apparently sprintf() does not return a value. zlib
  can build but will be open to possible string-format security
  vulnerabilities.
Checking for errno.h... No.
Checking for mmap support... No.
root#