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