Linux: libXext + .xsession-errors log filling hard drive

[Silarn =| +P |=]

ISSUE
A version of libXext shipped with the Linux version of steam (specifically, the packaged version for Fedora) is causing the .xsession-errors file to fill up with "_xgeWireToEvent: Unknown extension 147, this should never happen." This quickly fills up hard drive space until the system is unusable until the file is deleted and the X server is restarted.

OS
Fedora 21 Alpha

STEPS
Have a working copy of Fedora 21, install and launch Steam. Observe the .xsession-errors file.

RESULTS
The drive space falls to 0 and the system starts hanging.

EXPECTED
There are no errors in the log file.

POSSIBLE RESOLUTION
As reported here (https://bugzilla.redhat.com/show_bug.cgi?id=1122011) this appears to be a bug in the libXext library. Supposedly, a patched version of this library (http://patchwork.freedesktop.org/patch/22124/) fixes this issue.

TEMPORARY WORKAROUND
Delete the .xsession-errors file. This stops the file from being written into until a new xsession is started. That, or use one of several workarounds to prevent the xsession-errors file from being written into. Which means having no log to discover and fix these issues...

ADDENDUM
I have installed the patched f22 version of libXext, but this does not fix the errors generated when Steam is opened, so I'm assuming there's a packaged version of the library.

[yalla]

This bug needs more attention. The library libXext.so was already patched in Fedora 21 but Steam ships it's own - still broken - version of this library. For instance, from my $HOME:

$ find . -name "libXext*"
./share/Steam/ubuntu12_32/steam-runtime/amd64/usr/lib/x86_64-linux-gnu/libXext.so.6
./share/Steam/ubuntu12_32/steam-runtime/amd64/usr/lib/x86_64-linux-gnu/libXext.so.6.4.0
./share/Steam/ubuntu12_32/steam-runtime/i386/usr/lib/i386-linux-gnu/libXext.so.6
./share/Steam/ubuntu12_32/steam-runtime/i386/usr/lib/i386-linux-gnu/libXext.so.6.4.0
./share/Steam/ubuntu12_32/steam-runtime.old/amd64/usr/lib/x86_64-linux-gnu/libXext.so.6
./share/Steam/ubuntu12_32/steam-runtime.old/amd64/usr/lib/x86_64-linux-gnu/libXext.so.6.4.0
./share/Steam/ubuntu12_32/steam-runtime.old/i386/usr/lib/i386-linux-gnu/libXext.so.6
./share/Steam/ubuntu12_32/steam-runtime.old/i386/usr/lib/i386-linux-gnu/libXext.so.6.4.0

See also this issue on Github: https://github.com/ValveSoftware/steam-for-linux/issues/3364

To see how bad it is:

$ sudo journalctl --since 08:00:00 | grep xgeWire | wc -l
[sudo] password for alex: 
86698

However, to be honest, I didn't verify yet if Steam is actually using this version of libXext, as the report on Github suggests. Will do that now.

[citRa]

As a temporary workaround, I symlinked my Fedora 21 libXext.so files (both x86_64 and i386) to Steam's. Seems to be working well so far.