安装libpng提示#configure: error: zlib not installed

解决方法：
1.[root@localhost src]# cd zlib-1.2.3
2.[root@localhost zlib-1.2.3]# make clean
3.[root@localhost zlib-1.2.3]# ./configure
4.[root@localhost zlib-1.2.3]# make && make install
5.[root@localhost src]# cd libpng-1.2.31
6.[root@localhost libpng-1.2.31]# ./configure --prefix=/usr/local/libpng
7.[root@localhost libpng-1.2.31]# make && make install