Tom Anderson authored Apr 11, 2018 and Akira TAGOH committed Apr 17, 2018

realfilename is the file name after sysroot adjustments.  It should be used
instead of filename in the call to FcOpen() which forwards the name directly to
open().

Though I don't explicitly request a sysroot, I was getting error messages saying
"failed reading config file".  This CL fixes the error spam.