I had some trouble, maybe if someone else has the same trouble I can help.
1. I downloaded the source code at the pdflib site
2. I unpacked it and ran the configure and make commands and such. So far so good.
3. I realized that unlike the full version, this doesn’t come with the php extension bindings.
4. Tried to use pear install pdflib like the instructions said, but that failed, so I tried pecl, but it claimed my gcc didn’t work:
# pear install pdflib
No releases available for package “pear.php.net/pdflib” – package pecl/pdflib can be installed with “pecl install pdflib”
Cannot initialize ‘pdflib’, invalid or missing package file
Package “pdflib” is not valid
# pecl install pdflib
downloading pdflib-2.1.5.tgz …
Starting to download pdflib-2.1.5.tgz (55,579 bytes)
………….done: 55,579 bytes
10 source files, building
PHP Api Version: 20041225
Zend Module Api No: 20060613
Zend Extension Api No: 220060519
1. path to pdflib installation? :
1-1, ‘all’, ‘abort’, or Enter to continue: 1
path to pdflib installation?  : /usr/local
1. path to pdflib installation? : /usr/local
1-1, ‘all’, ‘abort’, or Enter to continue:
building in /var/tmp/pear-build-root/pdflib-2.1.5
running: /root/tmp/pear/pdflib/configure –with-pdflib=/usr/local
checking for egrep… grep -E
checking for a sed that does not truncate output… /bin/sed
checking for gcc… gcc
checking for C compiler default output file name… a.out
checking whether the C compiler works… configure: error: cannot run C compiled programs.
If you meant to cross compile, use `–host’.
See `config.log’ for more details.
ERROR: `/root/tmp/pear/pdflib/configure –with-pdflib=/usr/local’ failed
So that failed. I don’t know why, because my gcc does work. Anyway, the solution was to start the pecl process, then open another terminal window and copy the /root/tmp/pear/pdflib/ files to another directory.
Then manually run configure –with-pdflib=/usr/local there.
(I also ran into trouble because I wasn’t giving /usr/local as the directory. I was giving /usr/local/lib which was where libpdf.so was. Trouble was, it needed pdflib.h which was in /usr/local/include. So giving /usr/local it knows to look both places. The error code I was getting was: configure: error: pdflib.h not found! Check the path passed to –with-pdflib=
Then run make, then make test, then make install, and you’re done! You should now have pdf.so in your php extension directory, which is extension_dir in your php.ini file.
Hope that helps anyone googling for a solution based on error codes they’ve gotten.