Libpng Compiling related issues

Help: Libpng compilation problem
The following error occurred while compiling libpng:

/usr/bin/ld:cannot Find-lz
Collect2:ld returned 1 exit status
MAKE[1]: * * [libpng12.la] Error 1
MAKE[1]: Leaving directory '/usr/local/src/libpng-1.2.31 '
Make: * * * [ALL] Error 2



/**
* Zlib has been installed.
*/

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It's supposed to be something else.
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Check if your system has Libtool installed, you can use Rpm-qa
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grep Libtool

No, just install it with yum install libtool//.

JPEG compiled, okay?

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I don't think I've had a problem like this.
Libtool:link: ' l ' cannot specify a relative Directory//libtool: Link: '-L ' cannot specify related directory

Recompile it, give you two URLs, provide reference
CentOS installation of the GD library process: http://www.tabcn.cn/post/18.html
CentOS 5.5 under source installation configuration apache,php5.2.14,mysql:http://www.linux99.com/bbs/thread-36-1-1.html

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