Fix mac-specific STR#2999. Use PostScript font name to ask the system for a font, and full font name
to display a font name.

git-svn-id: http://seriss.com/public/fltk/fltk/branches/branch-1.3@10011 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
After r.10011 that removed the q_name member from class Fl_Font_Descriptor, change in gl_font() was needed.

git-svn-id: http://seriss.com/public/fltk/fltk/branches/branch-1.3@10012 ea41ed52-d2ee-0310-a9c1-e6b18d33e121