relocatable-prog: Use $ORIGIN trick on more platforms. * m4/relocatable.m4 (gl_RELOCATABLE_BODY): Use $ORIGIN trick also on FreeBSD >= 7.3, DragonFly >= 3.0, NetBSD >= 8.0, OpenBSD >= 5.4, Solaris >= 10, Haiku. But don't use it on Android. * build-aux/reloc-ldflags: Allow the use of the $ORIGIN trick also on Hurd, FreeBSD, DragonFly, NetBSD, OpenBSD, Solaris, Haiku.

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