Use gstreamer mirror as primary source for win-nasm and win-flex-bison
commit 439dfa29:
win-nasm: Error out if accidentally called on non-Windows
commit 352b8381:
win-nasm: Use gstreamer mirror as primary source
nasm.us went down today and broke all our CI. Use the gstreamer mirror
as the primary source and fallback to nasm.us if that's down.
commit 2f11c43f:
win-flex-bison: Use gstreamer mirror as primary source
Use the gstreamer mirror as the primary source and fallback to
upstream if it's down.
Edited by Nirbheek Chauhan