build: allow cros-compilation on chromeOS

- Request LIBTOOL to be used
- Set topbuildir based on a Makefile variable to call libtool
- Use /usr/local instead of /var for xfstest final location
- Move macros from aclocal.m4 to acinclude.m4, aclocal.m4 is autogenerated.
- Use autoconf variables @prefix@, @exec_prefix@.

The regular way of compiling xfstests - make - remains.
But it now runs autoreconf and libtoolize -i to produce a valid
configure.
Verified with 'make install --dry-run' that files are installed at the
same place.
Verified compiling in chromeOS chroot works as well.

[eguan: resolve merge conflicts and update .gitignore and remove
generated files by realclean]

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

include/builddefs.in

@@ -7,6 +7,8 @@
 ifndef _BUILDDEFS_INCLUDED_
 _BUILDDEFS_INCLUDED_ = 1
 
+top_builddir=$(TOPDIR)
+
 DEBUG = @debug_build@
 OPTIMIZER = @opt_build@
 MALLOCLIB = @malloc_lib@
@@ -24,6 +26,7 @@ LIBUUID = @libuuid@
 LIBHANDLE = @libhdl@
 LIBDM = @libdm@
 LIBTEST = $(TOPDIR)/lib/libtest.la
+prefix = @prefix@
 
 PKG_NAME        = @pkg_name@
 PKG_USER        = @pkg_user@
@@ -32,10 +35,8 @@ PKG_RELEASE     = @pkg_release@
 PKG_VERSION     = @pkg_version@
 PKG_PLATFORM    = @pkg_platform@
 PKG_DISTRIBUTION= @pkg_distribution@
-PKG_SBIN_DIR    = @sbindir@
-# A bit of a hack; by rights only state should probably go here
-# But for now ...
-PKG_LIB_DIR     = /var/lib/@pkg_name@
+PKG_LIB_DIR     = $(DESTDIR)@exec_prefix@/@pkg_name@
+
 
 CC              = @cc@
 AWK             = @awk@