nixpkgs/pkgs/development/libraries/vulkan-loader/use-xdg-paths.patch

diff --git a/loader/loader.c b/loader/loader.c
index a950ea1..9462d05 100644
--- a/loader/loader.c
+++ b/loader/loader.c
@@ -2671,6 +2671,94 @@ static VkResult loader_get_manifest_files(
         }
     }
 
+#if !defined(_WIN32)
+    if (home_location && override == NULL) {
+        char *xdgconfdirs = secure_getenv("XDG_CONFIG_DIRS");
+        char *xdgdatadirs = secure_getenv("XDG_DATA_DIRS");
+        char *cur, *src = loc;
+        size_t src_size = strlen(src), rel_size = strlen(home_location);
+        size_t size = 0;
+
+        if (src_size > 0)
+            size += src_size + 1;
+
+        if (xdgconfdirs == NULL)
+            xdgconfdirs = "/etc/xdg";
+        if (xdgdatadirs == NULL)
+            xdgdatadirs = "/usr/local/share:/usr/share";
+
+        for (char *x = xdgconfdirs; *x; ++x)
+            if (*x == PATH_SEPERATOR) size += rel_size;
+        size += strlen(xdgconfdirs) + rel_size + 1;
+        for (char *x = xdgdatadirs; *x; ++x)
+            if (*x == PATH_SEPERATOR) size += rel_size;
+        size += strlen(xdgdatadirs) + rel_size + 1;
+
+#if defined(LOCALPREFIX)
+        size += strlen(LOCALPREFIX "/" SYSCONFDIR) + rel_size + 1;
+        size += strlen(LOCALPREFIX "/" DATADIR) + rel_size + 1;
+#endif
+
+        loc = cur = loader_stack_alloc(size);
+        if (cur == NULL) {
+            loader_log(inst, VK_DEBUG_REPORT_ERROR_BIT_EXT, 0,
+                        "Out of memory can't get manifest files");
+            res = VK_ERROR_OUT_OF_HOST_MEMORY;
+            goto out;
+        }
+
+        if (src_size > 0) {
+          memcpy(cur, src, src_size);
+          cur += src_size;
+          *cur++ = PATH_SEPERATOR;
+        }
+
+        src = xdgconfdirs;
+        for (char *x = src;; ++x) {
+            if (*x == PATH_SEPERATOR || *x == 0) {
+                size_t s = x - src;
+                memcpy(cur, src, s); cur += s;
+                memcpy(cur, home_location, rel_size); cur += rel_size;
+                *cur++ = PATH_SEPERATOR;
+                if (*x == 0)
+                    break;
+                src = ++x;
+            }
+        }
+
+#if defined(LOCALPREFIX)
+        strcpy(cur, LOCALPREFIX "/" SYSCONFDIR);
+        cur += strlen(cur);
+        memcpy(cur, home_location, rel_size); cur += rel_size;
+        *cur++ = PATH_SEPERATOR;
+#endif
+
+        src = xdgdatadirs;
+        for (char *x = src;; ++x) {
+            if (*x == PATH_SEPERATOR || *x == 0) {
+                size_t s = x - src;
+                memcpy(cur, src, s); cur += s;
+                memcpy(cur, home_location, rel_size); cur += rel_size;
+                *cur++ = PATH_SEPERATOR;
+                if (*x == 0)
+                    break;
+                src = ++x;
+            }
+        }
+
+#if defined(LOCALPREFIX)
+        strcpy(cur, LOCALPREFIX "/" DATADIR);
+        cur += strlen(cur);
+        memcpy(cur, home_location, rel_size); cur += rel_size;
+        *cur++ = PATH_SEPERATOR;
+#endif
+
+        loc[size - 1] = 0;
+        assert(cur == loc + size);
+        list_is_dirs = true;
+    }
+#endif
+
     // Print out the paths being searched if debugging is enabled
     loader_log(inst, VK_DEBUG_REPORT_DEBUG_BIT_EXT, 0,
                "Searching the following paths for manifest files: %s\n", loc);
diff --git a/loader/vk_loader_platform.h b/loader/vk_loader_platform.h
index 3a02640..70a2652 100644
--- a/loader/vk_loader_platform.h
+++ b/loader/vk_loader_platform.h
@@ -57,35 +57,10 @@
 #define VULKAN_ILAYERCONF_DIR "implicit_layer.d"
 #define VULKAN_LAYER_DIR      "layer"
 
-#if defined(LOCALPREFIX)
-#define LOCAL_DRIVERS_INFO                                                     \
-    LOCALPREFIX "/" SYSCONFDIR VULKAN_DIR VULKAN_ICDCONF_DIR ":"               \
-    LOCALPREFIX "/" DATADIR    VULKAN_DIR VULKAN_ICDCONF_DIR ":"
-#define LOCAL_ELAYERS_INFO                                                     \
-    LOCALPREFIX "/" SYSCONFDIR VULKAN_DIR VULKAN_ELAYERCONF_DIR ":"            \
-    LOCALPREFIX "/" DATADIR    VULKAN_DIR VULKAN_ELAYERCONF_DIR ":"
-#define LOCAL_ILAYERS_INFO                                                     \
-    LOCALPREFIX "/" SYSCONFDIR VULKAN_DIR VULKAN_ILAYERCONF_DIR ":"            \
-    LOCALPREFIX "/" DATADIR    VULKAN_DIR VULKAN_ILAYERCONF_DIR ":"
-#else
-#define LOCAL_DRIVERS_INFO
-#define LOCAL_ELAYERS_INFO
-#define LOCAL_ILAYERS_INFO
-#endif
-
-#define DEFAULT_VK_DRIVERS_INFO                                                \
-    LOCAL_DRIVERS_INFO                                                         \
-    "/"  SYSCONFDIR VULKAN_DIR VULKAN_ICDCONF_DIR ":"                          \
-    "/usr/" DATADIR VULKAN_DIR VULKAN_ICDCONF_DIR
+#define DEFAULT_VK_DRIVERS_INFO ""
 #define DEFAULT_VK_DRIVERS_PATH ""
-#define DEFAULT_VK_ELAYERS_INFO                                                \
-    LOCAL_ELAYERS_INFO                                                         \
-    "/"  SYSCONFDIR VULKAN_DIR VULKAN_ELAYERCONF_DIR ":"                       \
-    "/usr/" DATADIR VULKAN_DIR VULKAN_ELAYERCONF_DIR
-#define DEFAULT_VK_ILAYERS_INFO                                                \
-    LOCAL_ILAYERS_INFO                                                         \
-    "/"  SYSCONFDIR VULKAN_DIR VULKAN_ILAYERCONF_DIR ":"                       \
-    "/usr/" DATADIR VULKAN_DIR VULKAN_ILAYERCONF_DIR
+#define DEFAULT_VK_ELAYERS_INFO ""
+#define DEFAULT_VK_ILAYERS_INFO ""
 #define DEFAULT_VK_LAYERS_PATH ""
 #if !defined(LAYERS_SOURCE_PATH)
 #define LAYERS_SOURCE_PATH NULL