[El] php-mapserver is compiled WITHOUT RGBA_PNG support

[Pavel Iacovlev]

Good day,

This option is needed to create 8bit transparent PNGs, and by default
is available in PHP Mapscript packages such as MS4W, UbuntuGIS,
OpenSUSE Geo Repositories. Would be nice to have consistency in build
options.

To enable RGBA_PNG support PHP Mapscript needs to be compiled with
–with-experimental-png. Take note that this feature is not
experimental, it's just a name that stuck.