unsetenv etc.: port to Solaris 11 + GNU Emacs * lib/canonicalize-lgpl.c, lib/getaddrinfo.c, lib/getdelim.c: * lib/glob.c, lib/random_r.c, lib/setenv.c, lib/tsearch.c: * lib/unsetenv.c (_GL_ARG_NONNULL): Define before including <config.h>. GNU Emacs's <config.h> includes <stdlib.h> (which is not a great idea but is too painful to fix right now), and without this gnulib change <stdlib.h> was defining _GL_ARG_NONNULL incorrectly when compiling unsetenv.c on Solaris 11. Fix the problem for unsetenv.c, and fix other similar occurrences.

# Suppress a valgrind message about use of uninitialized memory in rawmemchr().
# This use is OK because it provides only a speedup.
{
    rawmemchr-value4
    Memcheck:Value4
    fun:rawmemchr
}
{
    rawmemchr-value8
    Memcheck:Value8
    fun:rawmemchr
}