media-video/ffmpeg: update live

Seems now does build-time shader compilation with USE=vulkan regardless
of USE=shaderc (the latter is for runtime shader compilation).

Arguably could consider merging USE=shaderc into USE=vulkan, albeit
it does allow binpkgs to skip a dep still.

An extra reason to merge is that USE="vulkan -shaderc" currently fails
to build in 9999 but unless ./configure starts requiring it that is
probably not intended and is temporary.

USE=gnutls also fails, seems due to missing headers at a glance.

Not going to worry about these for now, assume it'll be looked at
before long. Users may want to juggle USE or revert to release versions
meanwhile or report upstream to get fixes earlier.

Signed-off-by: Ionen Wolkens <ionen@gentoo.org>

media-video/ffmpeg/ffmpeg-9999.ebuild

@@ -1,4 +1,4 @@
-# Copyright 2025 Gentoo Authors
+# Copyright 2025-2026 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 EAPI=8
@@ -320,6 +320,7 @@ BDEPEND="
 	virtual/pkgconfig
 	amd64? ( dev-lang/nasm )
 	cuda? ( llvm-core/clang:*[llvm_targets_NVPTX] )
+	vulkan? ( media-libs/shaderc )
 	${FFMPEG_UNSLOTTED:+"
 		dev-lang/perl
 		doc? ( sys-apps/texinfo )