include: fix out-of-source-tree build
include: fix out-of-source-tree build

Fixes:

  cd alsa-lib
  if test -r Makefile; then
    make distclean
  fi
  mkdir build
  cd build
  ../configure
  make

Note:

  The srcdir is used for the symlinks to generated include files :-(
  I've not found a better (easy) way to fix this.

Fixes: https://github.com/alsa-project/alsa-lib/issues/136
Signed-off-by: Jaroslav Kysela <72edd5e1a572f82f059ccbb83c92b74d6cb051ff@perex.cz>

alsa-project/alsa-lib,alsa-project/alsa-lib,tiwai/alsa-lib,alsa-project/alsa-lib,tiwai/alsa-lib,alsa-project/alsa-lib,tiwai/alsa-lib,tiwai/alsa-lib