FcStrCopyFilename - create a complete path from a filename
#include <fontconfig/fontconfig.h>
FcChar8 * FcStrCopyFilename (const FcChar8 *s);
FcStrCopyFilename constructs an absolute pathname from s. It
converts any leading '~' characters in to the value of the HOME environment
variable, and any relative paths are converted to absolute paths using the
current working directory. Sequences of '/' characters are converted to a
single '/', and names containing the current directory '.' or parent directory
'..' are correctly reconstructed. Returns NULL if '~' is the leading character
and HOME is unset or disabled (see FcConfigEnableHome).