dérive linux ports

$ cat 0001-allow-software-vulkan.patch

diff --git a/src/include/libplacebo/vulkan.h b/src/include/libplacebo/vulkan.h
index f873f54c..47f1bfd3 100644
--- a/src/include/libplacebo/vulkan.h
+++ b/src/include/libplacebo/vulkan.h
@@ -267,6 +267,7 @@ struct pl_vulkan_params {
 
 // Default/recommended parameters. Should generally be safe and efficient.
 #define PL_VULKAN_DEFAULTS                              \
+    .allow_software = true,                             \
     .async_transfer = true,                             \
     .async_compute  = true,                             \
     /* enabling multiple queues often decreases perf */ \