loader: Change layer manifest file location env var to VK_LAYER_PATH

bug #14394
diff --git a/loader/vk_loader_platform.h b/loader/vk_loader_platform.h
index 3134b0e..41d6d47 100644
--- a/loader/vk_loader_platform.h
+++ b/loader/vk_loader_platform.h
@@ -93,7 +93,7 @@
 #define DEFAULT_VK_LAYERS_PATH \
     LOCAL_LAYERS_PATH \
     "/usr/" LIBDIR VULKAN_LAYER_DIR
-#define LAYERS_PATH_ENV "VK_LAYER_DIRS"
+#define LAYERS_PATH_ENV "VK_LAYER_PATH"
 
 // C99:
 #define PRINTF_SIZE_T_SPECIFIER    "%zu"
@@ -227,7 +227,7 @@
 #define DEFAULT_VK_DRIVERS_PATH "C:\\Windows\\System32;C:\\Windows\\SysWow64"
 #define DEFAULT_VK_LAYERS_INFO "SOFTWARE\\Khronos\\Vulkan\\ExplicitLayers;SOFTWARE\\Khronos\\Vulkan\\ImplicitLayers"
 #define DEFAULT_VK_LAYERS_PATH "C:\\Windows\\System32;C:\\Windows\\SysWow64"
-#define LAYERS_PATH_ENV "VK_LAYER_FOLDERS"
+#define LAYERS_PATH_ENV "VK_LAYER_PATH"
 
 // C99:
 // Microsoft didn't implement C99 in Visual Studio; but started adding it with