[Bug lto/54206] build in source dir breaks lto plugin detection

[andi-gcc at firstfloor dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54206

--- Comment #5 from Andi Kleen <andi-gcc at firstfloor dot org> 2012-10-04 18:50:52 UTC ---
This is the configure snippet glibc is using for this.
Someone with better autoconf-fu than me could add it


if test "`cd $srcdir; /bin/pwd`" = "`/bin/pwd`"; then
  AC_MSG_ERROR([you must configure in a separate build directory])
fi