FcFontMatch - Return best font
#include <fontconfig/fontconfig.h>
FcPattern * FcFontMatch (FcConfig *config, FcPattern *p, FcResult *result);
Finds the font in sets most closely matching pattern and returns
  the result of FcFontRenderPrepare for that font and the provided
  pattern. This function should be called only after FcConfigSubstitute
  and FcDefaultSubstitute have been called for p; otherwise the
  results will not be correct. If config is NULL, the current
  configuration is used.