Tweaking autotools-based buildsystem for W32 compatibility

[Ethan Blanton]

> --- pidgin-hg-c83a09a6e3d5/libpurple/protocols/jabber/Makefile.am.orig	2014-04-24 12:58:58.748001000 +0000
> +++ pidgin-hg-c83a09a6e3d5/libpurple/protocols/jabber/Makefile.am	2014-04-24 13:56:10.110728700 +0000
> @@ -125,7 +125,7 @@
>  libjabber_la_LIBADD  = @PURPLE_LIBS@ $(SASL_LIBS) $(LIBXML_LIBS) $(IDN_LIBS)\
>  	$(FARSTREAM_LIBS) \
>  	$(GSTREAMER_LIBS)
> -libjabber_la_LDFLAGS = @PLUGIN_LDFLAGS@
> +libjabber_la_LDFLAGS = -no-undefined
>  
>  libfacebook_la_SOURCES = libfacebook.c
>  libfacebook_la_LIBADD = libjabber.la

This seems bogus to me.  What's the deal?

Ethan