* bootstrap (modules): Add stpcpy, and pull in gnulib bits:
* gnulib/lib/stpcpy.c: New file.
* gnulib/m4/stpcpy.m4: New file.
* gnulib/lib/Makefile.am: Update.
* gnulib/m4/gnulib-cache.m4: Update.
* gnulib/m4/gnulib-comp.m4: Update.