bug#20997: 25.0.50; display broken

[Mark Oteiza]

Glenn Morris <rgm@gnu.org> writes:
> FWIW I did a with-cairo build of current master and saw no such issues.

I see lots of display errors, though erratically. Here's a screenshot, erasing
the display with an X window

https://i.imgur.com/z8h0z74.png

In GNU Emacs 25.0.50.1 (x86_64-unknown-linux-gnu, X toolkit, cairo version 
1.14.2, Xaw scroll bars)
 of 2015-09-11
Repository revision: e125dce50b2fa1c5f57f6ca00ea679437593bdc4
Configured using:
 'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
 --localstatedir=/var --without-gconf --without-imagemagick --with-cairo
 --with-x-toolkit=lucid 'CFLAGS=-march=x86-64 -mtune=generic -O2 -pipe
 -fstack-protector-strong --param=ssp-buffer-size=4'
 CPPFLAGS=-D_FORTIFY_SOURCE=2
 LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro'

Configured features:
XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND GPM DBUS GSETTINGS NOTIFY ACL
GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB TOOLKIT_SCROLL_BARS
LUCID X11