refactor: use compile time env var for vulkan icd base path

Author: oknozor

README.md

@@ -1,6 +1,6 @@
 # Freedesktop Desktop Entry Specification
 
-This crate provides a library for efficiently parsing [Desktop Entry](https://specifications.freedesktop.org/desktop-entry-spec/latest/index.html) files.
+This crate provides a library for efficiently parsing and launching [Desktop Entry](https://specifications.freedesktop.org/desktop-entry-spec/latest/index.html) files.
 
 ```rust
 use std::fs;

src/exec/dbus.rs

@@ -62,7 +62,7 @@ impl DesktopEntry<'_> {
             return false;
         }
 
-        let dbus_proxy = dbus_proxy;
+        let dbus_proxy = dbus_proxy.unwrap();
         let dbus_names = dbus_proxy.list_activatable_names();
 
         if dbus_names.is_err() {

src/exec/graphics.rs

@@ -7,7 +7,7 @@ use std::io;
 use std::ops::Deref;
 use std::path::{Path, PathBuf};
 
-const VULKAN_ICD_PATH: &str = "/usr/share/vulkan/icd.d";
+const VULKAN_ICD_PATH: &str = std::env!("VULKAN_ICD_PATH", "must define system Vulkan ICD path (ex: `/usr/share/vulkan/icd.d`)");
 
 #[derive(Debug, Default)]
 pub struct Gpus {

src/exec/mod.rs

@@ -14,7 +14,7 @@ pub mod error;
 mod graphics;
 
 impl DesktopEntry<'_> {
-    /// Execute the given desktop entry `Exec` key with either the default gpu or
+    /// Launch the given desktop entry either via dbus or via its `Exec` key with the default gpu or
     /// the alternative one if available.
     pub fn launch(&self, uris: &[&str], prefer_non_default_gpu: bool) -> Result<(), ExecError> {
         match Connection::session() {