gd & fontpath (could not find/open font)

[Mojca M. <moj...@gm...>]

Dear Gnuplot developers,

I'm still experiencing a problem with

> set term png
    Terminal type set to 'png'
    Could not find/open font when opening font "arial", using internal
non-scalable font
> show fontpath
    fontpath is
    system fontpath is "/System/Library/Fonts" "/Library/Fonts"
"/Users/myusername/Library/Fonts"

on Mac OS X. After some experiments I came to conclusion that the
reason might have been Microsoft Office which installed the file
    /Library/Fonts/Microsoft/Arial.ttf
and removed
    /Library/Fonts/Arial.ttf
and I guess that GD2 is unable to search recursively in font
directories. fc-list finds the font without problems and could be used
to search for fonts, but last time Ethan had concerns about enabling
FontConfig:

> There seem to be bugs in the libgd function gdFTUseFontConfig(), in that
> once you turn it on you can never turn it off again.  Unless that is fixed,
> it means that gnuplot scripts using a mixture of self-supplied fonts and
> fontconfig-installed fonts will fail.   That would break most of my
> web tools, for example, which provide private font files.

Assuming that font-config isn't/won't be enabled (it doesn't look very
promissing that gd team will release a new version in any reasonable
time), I have the following questions:

1.) What is (or should be) the exact algorithm to search for arial?
How could I convince gnuplot (gd2) to automatically find Arial.ttf
even when it resides in /Library/Fonts/Microsoft/Arial.ttf, without my
manual intervention? How should I tell gnuplot (gd2) to search
recursively through all the three font paths mentioned above?

2.) What is the difference between "fontpath" and "system fontpath"
mentioned above?

Thank you,
    Mojca