Workaround gnome-shell including uninitialized memory when pasting
from the clipboard. Where `read` would not write data into the range
return by the length.
Reading from the pipe into a power-of-two buffer
works around the problem.
It's not clear why this only impacts gnome-shell - as there is no
significant down-side to changing the buffer size, apply a workaround.
Ref !106091.
cb4f7cac24