emacs copying ${STAGING_DIR_TARGET} - wtf?

[Graham Gower <graham.gower@gmail.com>]

emacs.inc has this nugget in do_compile_prepend():
cp -pPR ${STAGING_DIR_TARGET}/* $treedir

During a world build, both emacs and emacs-x11 copy some 5GB into
their work dirs. This really seems like overkill.

Could someone familiar with building emacs take a look to see if
there is a reasonable alternative?

thanks,
-Graham

PS: emacs and emacs-x11 fail for me in do_compile.

NOTE: make -j 12 QEMU=qemu-mipsel  -s 1048576 -L /mnt/oe/tmp/work/mipsel-oe-linux/emacs-22.3-r1/qemu-treedir 
cd lib-src; make all - --jobserver-fds=3,22 -j \
	  CC='mipsel-oe-linux-gcc -march=mips32' CFLAGS='-isystem/mnt/oe/tmp/sysroots/mipsel-oe-linux/usr/include -fexpensive-optimizations -fomit-frame-pointer -frename-registers -Os' CPPFLAGS='-D_BSD_SOURCE  -isystem/mnt/oe/tmp/sysroots/mipsel-oe-linux/usr/include' \
	  LDFLAGS='-L/mnt/oe/tmp/sysroots/mipsel-oe-linux/usr/lib -Wl,-rpath-link,/mnt/oe/tmp/sysroots/mipsel-oe-linux/usr/lib -Wl,-O1 -Wl,-znocombreloc' MAKE='make'
make[1]: Entering directory `/mnt/oe/tmp/work/mipsel-oe-linux/emacs-22.3-r1/emacs-22.3/lib-src'
Makefile:149: *** commands commence before first target.  Stop.
make[1]: Leaving directory `/mnt/oe/tmp/work/mipsel-oe-linux/emacs-22.3-r1/emacs-22.3/lib-src'
make: *** [lib-src] Error 2
FATAL: oe_runmake failed