Add XMMS macro to acinclude.m4, since it's a commonly missing macro.
Add XMMS macro to acinclude.m4, since it's a commonly missing macro.

Original commit message from CVS:
Add XMMS macro to acinclude.m4, since it's a commonly missing macro.
This joins the ALSA macro, which was already in acinclude.m4
We need some more consistent scheme for dealing with these... :(

krichter722/gstreamer,StreamUtils/gstreamer,centricular/gstreamer,magcius/gstreamer,drothlis/gstreamer,mparis/gstreamer,Distrotech/gstreamer,krieger-od/gstreamer,mrchapp/gstreamer,shelsonjava/gstreamer,collects/gstreamer,jpakkane/gstreamer,shelsonjava/gstreamer,ahmedammar/platform_external_gst_gstreamer,lovebug356/gstreamer,krieger-od/gstreamer,mparis/gstreamer,magcius/gstreamer,collects/gstreamer,Lachann/gstreamer,mparis/gstreamer,jpakkane/gstreamer,centricular/gstreamer,mparis/gstreamer,cablelabs/gstreamer,cablelabs/gstreamer,mrchapp/gstreamer,jpxiong/gstreamer,justinjoy/gstreamer,cablelabs/gstreamer,drothlis/gstreamer,justinjoy/gstreamer,cfoch/gstreamer,ensonic/gstreamer,surround-io/gstreamer,lubosz/gstreamer,magcius/gstreamer,lovebug356/gstreamer,Lachann/gstreamer,ensonic/gstreamer,ahmedammar/platform_external_gst_gstreamer,krichter722/gstreamer,krieger-od/gstreamer,StreamUtils/gstreamer,krichter722/gstreamer,krichter722/gstreamer,krieger-od/gstreamer,lubosz/gstreamer,Distrotech/gstreamer,ylatuya/gstreamer,StreamUtils/gstreamer,surround-io/gstreamer,jpakkane/gstreamer,centricular/gstreamer,ensonic/gstreamer,Lachann/gstreamer,drothlis/gstreamer,justinjoy/gstreamer,mrchapp/gstreamer,lubosz/gstreamer,StreamUtils/gstreamer,magcius/gstreamer,justinjoy/gstreamer,lovebug356/gstreamer,ensonic/gstreamer,Lachann/gstreamer,cfoch/gstreamer,ensonic/gstreamer,Distrotech/gstreamer,ahmedammar/platform_external_gst_gstreamer,collects/gstreamer,surround-io/gstreamer,surround-io/gstreamer,ylatuya/gstreamer,lovebug356/gstreamer,Lachann/gstreamer,drothlis/gstreamer,collects/gstreamer,Distrotech/gstreamer,jpxiong/gstreamer,jpxiong/gstreamer,ylatuya/gstreamer,lubosz/gstreamer,shelsonjava/gstreamer,ahmedammar/platform_external_gst_gstreamer,cablelabs/gstreamer,jpxiong/gstreamer,krieger-od/gstreamer,lovebug356/gstreamer,krichter722/gstreamer,shelsonjava/gstreamer,cablelabs/gstreamer,cfoch/gstreamer,ylatuya/gstreamer,surround-io/gstreamer,centricular/gstreamer,collects/gstreamer,jpakkane/gstreamer,cfoch/gstreamer,lubosz/gstreamer,Distrotech/gstreamer,mrchapp/gstreamer,drothlis/gstreamer,shelsonjava/gstreamer,cfoch/gstreamer,magcius/gstreamer,mrchapp/gstreamer,justinjoy/gstreamer,ahmedammar/platform_external_gst_gstreamer,centricular/gstreamer,StreamUtils/gstreamer,mparis/gstreamer,jpakkane/gstreamer,ylatuya/gstreamer,jpxiong/gstreamer