Created attachment 844339 [details] Patch for rawhide As noted in the spec file, widl is compiled for each target so that each knows where to find that toolchain's IDL files. But AFAICS this isn't actually happening. This is handled through the DEFAULT_INCLUDE_DIR define from mingw-w64-tools/widl/Makefile.am:widl_CPPFLAGS, but the builtin value there (==$prefix/$target/include) is correct only for a non-sysroot setup. As mingw*-headers is installed into the sysroot, this needs to be changed. Fixing this "properly" upstream to allow for sysroot as an option is going to be tricky, but patching this just for Fedora is easy enough. Patch for rawhide attached, but this affects F19 and F20 as well.
mingw-w64-tools-3.0.0-1.fc20 has been submitted as an update for Fedora 20. https://admin.fedoraproject.org/updates/mingw-w64-tools-3.0.0-1.fc20
Package mingw-w64-tools-3.0.0-1.fc20: * should fix your issue, * was pushed to the Fedora 20 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing mingw-w64-tools-3.0.0-1.fc20' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-2014-0253/mingw-w64-tools-3.0.0-1.fc20 then log in and leave karma (feedback).
mingw-w64-tools-3.0.0-1.fc20 has been pushed to the Fedora 20 stable repository. If problems still persist, please make note of it in this bug report.