bug#29013: 25.3; [wishlist] do not yank whitespace

[Alex Branham]

It would be nice to have an option so that yank never returns pure whitespace. 
The current behavior is such that if we have:

#+BEGIN_EXAMPLE
some text here

some text there|
#+END_EXAMPLE

with | representing where point is, if you execute C-SPC C-a M-w C-p C-k C-p 
C-y then you end up with:

#+BEGIN_EXAMPLE

some text here
some text there
#+END_EXAMPLE

but I would like to end up with:

#+BEGIN_EXAMPLE
some text there
some text here
some text there
#+END_EXAMPLE

Thanks,
Alex


In GNU Emacs 25.3.1 (x86_64-pc-linux-gnu, GTK+ Version 3.22.19)
 of 2017-09-16 built on juergen
Windowing system distributor 'The X.Org Foundation', version 11.0.11905000
Configured using:
 'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
 --localstatedir=/var --with-x-toolkit=gtk3 --with-xft --with-modules
 'CFLAGS=-march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong
 -fno-plt' CPPFLAGS=-D_FORTIFY_SOURCE=2
 LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GCONF GSETTINGS
NOTIFY ACL GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 MODULES

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix