Search for a font and prepare it for later use with PDF_setfont().
The metrics will be loaded, and if embed is
nonzero, the font file will be checked, but not yet used.
encoding is one of builtin,
macroman, winansi,
host, a user-defined encoding name or the name of
a CMap.
Parameter embed is optional before PHP 4.3.5 or
with PDFlib less than 5.
This function is deprecated since PDFlib version 5, use PDF_load_font() instead.