Improve build procedure and instructions (#28)

Fixes issues pointed out in #27:
* spirv_tools-sys was build in non-test profiles
* By default ZLUDA dll has a wrong name
* We relied on third-party OpenCL installation on Windows
* We encouraged building debug configuration
* We didn't provide build information for developers (cmake, python, submodules)

2 files changed, 6 insertions, 7 deletions

diff --git a/level_zero-sys/build.rs b/level_zero-sys/build.rs
index 4a638ec..0d2488c 100644
--- a/level_zero-sys/build.rs
+++ b/level_zero-sys/build.rs
@@ -1,18 +1,17 @@
 use env::VarError;
 use std::{env, path::PathBuf};
 
-fn main() -> Result<(), VarError> {
+fn main() -> Result<(), VarError> { 
     println!("cargo:rustc-link-lib=dylib=ze_loader");
-    if env::var("CARGO_CFG_WINDOWS").is_ok() {
+    if cfg!(windows) {
         let env = env::var("CARGO_CFG_TARGET_ENV")?;
-        if env == "gnu" {
-            println!("cargo:rustc-link-search=native=C:\\Windows\\System32");
-        } else {
+        if env == "msvc" {
             let mut path = PathBuf::from(env::var("CARGO_MANIFEST_DIR")?);
-            path.push("src");
+            path.push("lib");
             println!("cargo:rustc-link-search=native={}", path.display());
+        } else {
+            println!("cargo:rustc-link-search=native=C:\\Windows\\System32");
         };
     }
-    println!("cargo:rerun-if-changed=build.rs");
     Ok(())
 }
diff --git a/level_zero-sys/src/ze_loader.lib b/level_zero-sys/lib/ze_loader.lib
index 661240c..661240c 100644
--- a/level_zero-sys/src/ze_loader.lib
+++ b/level_zero-sys/lib/ze_loader.lib