qtubuntu-media fails to build against Qt 5.1.1 on i386 (only)

I've been doing rebuilds of a good selection of packages in our daily release system against Qt 5.1.1, and it seems qtubuntu-media continues to build fine on armhf and amd64 but fails on i386: https://launchpad.net/~canonical-qt5-edgers/+archive/qt5-daily/+sourcepub/3448025/+listing-archive-extra (build log https://launchpadlibrarian.net/148512120/buildlog_ubuntu-saucy-i386.qtubuntu-media_0.7.1%2B13.10.20130627-0ubuntu1_FAILEDTOBUILD.txt.gz)

Most of the 30+ packages build fine against Qt 5.1.1, so it seems it's more about packages that use some low-level OpenGL functions that maybe have small issues. If you need to do something Qt 5.1 specific, see eg. https://code.launchpad.net/~aacid/unity8/supportqt51/+merge/177365 on how to #ifdef on the Qt version to support both 5.0.x and 5.1.x.

To reproduce:
sudo apt-add-repository ppa:canonical-qt5-edgers/qt5-beta-proper
sudo apt-get update
sudo apt-get dist-upgrade
+ build

To revert back to archive versions:

sudo ppa-purge ppa:canonical-qt5-edgers/qt5-beta-proper