gstreamer.mk: fix more portability issues
gstreamer.mk: fix more portability issues

jackjansen/cerbero-2013,OptoFidelity/cerbero,AlertMe/cerbero,fluendo/cerbero,shoreflyer/cerbero,AlertMe/cerbero,brion/cerbero,EricssonResearch/cerbero,freedesktop-unofficial-mirror/gstreamer-sdk__cerbero,flexVDI/cerbero,flexVDI/cerbero,flexVDI/cerbero,nirbheek/cerbero,jackjansen/cerbero-2013,OptoFidelity/cerbero,flexVDI/cerbero,atsushieno/cerbero,freedesktop-unofficial-mirror/gstreamer-sdk__cerbero,GStreamer/cerbero,cee1/cerbero-mac,lubosz/cerbero,ford-prefect/cerbero,lubosz/cerbero,brion/cerbero,ramaxlo/cerbero,ikonst/cerbero,nzjrs/cerbero,sdroege/cerbero,ford-prefect/cerbero,ikonst/cerbero,sdroege/cerbero,justinjoy/cerbero,nicolewu/cerbero,atsushieno/cerbero,GStreamer/cerbero,nzjrs/cerbero,multipath-rtp/cerbero,EricssonResearch/cerbero,AlertMe/cerbero,nirbheek/cerbero-old,GStreamer/cerbero,freedesktop-unofficial-mirror/gstreamer__cerbero,nzjrs/cerbero,ylatuya/cerbero,cee1/cerbero-mac,cee1/cerbero-mac,superdump/cerbero,nirbheek/cerbero,GStreamer/cerbero,fluendo/cerbero,freedesktop-unofficial-mirror/gstreamer__sdk__cerbero,EricssonResearch/cerbero,superdump/cerbero,atsushieno/cerbero,AlertMe/cerbero,ikonst/cerbero,davibe/cerbero,fluendo/cerbero,ford-prefect/cerbero,shoreflyer/cerbero,BigBrother-International/gst-cerbero,justinjoy/cerbero,EricssonResearch/cerbero,jackjansen/cerbero-2013,shoreflyer/cerbero,freedesktop-unofficial-mirror/gstreamer__cerbero,freedesktop-unofficial-mirror/gstreamer__sdk__cerbero,superdump/cerbero,ikonst/cerbero,jackjansen/cerbero,nzjrs/cerbero,justinjoy/cerbero,centricular/cerbero,nirbheek/cerbero,centricular/cerbero,jackjansen/cerbero-2013,multipath-rtp/cerbero,fluendo/cerbero,shoreflyer/cerbero,davibe/cerbero,BigBrother-International/gst-cerbero,freedesktop-unofficial-mirror/gstreamer-sdk__cerbero,OptoFidelity/cerbero,ramaxlo/cerbero,BigBrother-International/gst-cerbero,GStreamer/cerbero,sdroege/cerbero,centricular/cerbero,ramaxlo/cerbero,jackjansen/cerbero-2013,lubosz/cerbero,jackjansen/cerbero,nirbheek/cerbero-old,EricssonResearch/cerbero,nirbheek/cerbero,lubosz/cerbero,freedesktop-unofficial-mirror/gstreamer__sdk__cerbero,davibe/cerbero,multipath-rtp/cerbero,atsushieno/cerbero,ylatuya/cerbero,freedesktop-unofficial-mirror/gstreamer-sdk__cerbero,nirbheek/cerbero-old,freedesktop-unofficial-mirror/gstreamer__sdk__cerbero,OptoFidelity/cerbero,nicolewu/cerbero,nicolewu/cerbero,flexVDI/cerbero,brion/cerbero,jackjansen/cerbero,ramaxlo/cerbero,freedesktop-unofficial-mirror/gstreamer-sdk__cerbero,ylatuya/cerbero,multipath-rtp/cerbero,justinjoy/cerbero,nzjrs/cerbero,shoreflyer/cerbero,jackjansen/cerbero,superdump/cerbero,BigBrother-International/gst-cerbero,ylatuya/cerbero,centricular/cerbero,nirbheek/cerbero-old,centricular/cerbero,multipath-rtp/cerbero,freedesktop-unofficial-mirror/gstreamer__cerbero,BigBrother-International/gst-cerbero,cee1/cerbero-mac,ramaxlo/cerbero,ikonst/cerbero,brion/cerbero,atsushieno/cerbero,sdroege/cerbero,freedesktop-unofficial-mirror/gstreamer__cerbero,ford-prefect/cerbero,davibe/cerbero,AlertMe/cerbero,fluendo/cerbero,sdroege/cerbero,brion/cerbero