However, this has started breaking recently since the libjpeg and libpng installers don't always create a file called libjpeg.so. A lot of users are getting thrown by this. The outcome is a configure error like this:
checking whether to enable FTP support... no checking OpenSSL dir for FTP... no checking for GD support... yes checking for the location of libjpeg... ../usr/lib/ checking for the location of libpng... no checking for the location of libXpm... no checking for FreeType 1.x support... no checking for FreeType 2... no checking for T1lib support... no checking whether to enable truetype string function in GD... no checking whether to enable JIS-mapped Japanese font support in GD... no checking for fabsf... yes checking for floorf... yes configure: error: libjpeg.(a|so) not found. chris@brezhnev:/usr/src/php-5.2.6$
Running a 'locate libjpeg|grep so' on your system will probably reveal the following two files:
chris@brezhnev:/usr/src/php-5.2.6$ locate libjpeg| grep so /usr/lib/libjpeg.so.62 /usr/lib/libjpeg.so.62.0.0
So it's no wonder that you can't find libjpeg.so. It doesn't exist.
Mucky, thought it sounds, the solution to this problem is to simply copy the file over with it's expected name. You could also achieve the same with a symbolic link. Either way, your ./configure script will continue through to the end.