* Add gnulib files generated by gnulib-tool in build-aux, m4 and
grub-core/gnulib directories
* .bzignore: Add **/.deps and autogenerated gnulib files
* configure.ac: Assign auxiliary directory to build-aux, add invocation
of gnulib macros, add grub-core/gnulib/Makefile
* Makefile.am: Add gnulib directory in SUBDIRS (removing unnecessary .),
include m4 directory to aclocal.
* Makefile.util.def: Remove direct compilation of gnulib source files
and use the new grub-core/gnulib/libgnu.a.
* build-aux/config.rpath: move config.rpath from top directory to
build-aux
* conf/Makefile.common: Remove the macro _GL_UNUSED already defined
in gnulib headers
* conf/Makefile.extra-dist: Add m4/gnulib-cache.m4
* grub-core/Makefile.core.def: Remove unnecessary extra_dist
* grub-core/lib/posix_wrap/localcharset.h (locale_charset): Update
header.
* grub-core/lib/posix_wrap/langinfo.h (nl_langinfo): Return static
string.
