* .bzrignore: Add lib/alloca.h.
* Makefile.in (GNULIB_MODULES): Add alloca-opt.
* configure.in (AC_FUNC_ALLOCA): Remove almost all the alloca stuff,
as gnulib now does that for us. Put alloca check after gl_INIT.
* lib/gnulib.mk, m4/gl-comp.m4: Regenerate.
* lib/alloca.in.h, m4/alloca.m4: New files, from gnulib.