configure: fix decklink dependencies

We don't need libdl for win32/mingw.

Reviewed-by: James Almer <jamrial@gmail.com>
Signed-off-by: Marton Balint <cus@passwd.hu>

configure

@@ -3084,9 +3084,10 @@ avfoundation_indev_deps="avfoundation pthreads"
 avfoundation_indev_extralibs="-framework Foundation -framework CoreVideo -framework CoreMedia"
 bktr_indev_deps_any="dev_bktr_ioctl_bt848_h machine_ioctl_bt848_h dev_video_bktr_ioctl_bt848_h dev_ic_bt8xx_h"
 caca_outdev_deps="libcaca"
-decklink_indev_deps="decklink threads libdl"
+decklink_deps_any="libdl LoadLibrary"
+decklink_indev_deps="decklink threads"
 decklink_indev_extralibs="-lstdc++"
-decklink_outdev_deps="decklink threads libdl"
+decklink_outdev_deps="decklink threads"
 decklink_outdev_extralibs="-lstdc++"
 libndi_newtek_indev_deps="libndi_newtek libdl"
 libndi_newtek_indev_extralibs="-lndi"