fontconfig's %post scripts use grep and mkdir but there is no listed dependency on these programs.
When installing a system we are seeing that yum may decide to install fontconfig before grep and coreutils, which will cause the post script to not be run correctly.
Originally reported at http://dev.laptop.org/ticket/11856
Fixed in fontconfig-2.8.0-7.fc17
fontconfig-2.8.0-7.fc17 has been submitted as an update for Fedora 17.
The upstream report says "The fontconfig errors are harmless". Are there any issues that would indicate this needs to be fixed in Fedora 17 GOLD and not as a standard update?
Discussed in the 2012-05-18 blocker bug review meeting. This claims to be harmless error messages and could possibly result in temporary issues with building a font cache and slowing down font rendering. While unfortunate, does not seem critical and thus rejected as NTH.
fontconfig-2.8.0-7.fc17 has been pushed to the Fedora 17 stable repository. If problems still persist, please make note of it in this bug report.