alvr: Fix build with ffmpeg 8 compat (#461709)

pkgs/by-name/al/alvr/package.nix

@@ -27,6 +27,7 @@
   libva,
   libvdpau,
   libxkbcommon,
+  openapv,
   openssl,
   openvr,
   pipewire,
@@ -59,6 +60,15 @@ rustPlatform.buildRustPackage rec {
     })
   ];
 
+  postPatch = ''
+    substituteInPlace alvr/server_openvr/cpp/platform/linux/EncodePipelineVAAPI.cpp \
+      --replace-fail 'FF_PROFILE_H264_MAIN' 'AV_PROFILE_H264_MAIN' \
+      --replace-fail 'FF_PROFILE_H264_BASELINE' 'AV_PROFILE_H264_BASELINE' \
+      --replace-fail 'FF_PROFILE_H264_HIGH' 'AV_PROFILE_H264_HIGH' \
+      --replace-fail 'FF_PROFILE_HEVC_MAIN' 'AV_PROFILE_HEVC_MAIN' \
+      --replace-fail 'FF_PROFILE_AV1_MAIN' 'AV_PROFILE_AV1_MAIN'
+  '';
+
   env = {
     NIX_CFLAGS_COMPILE = toString [
       "-lbrotlicommon"
@@ -111,6 +121,7 @@ rustPlatform.buildRustPackage rec {
     libva
     libvdpau
     libxkbcommon
+    openapv
     openssl
     openvr
     pipewire