make cuda a feature

Author: Montana Low

Cargo.toml

@@ -16,6 +16,3 @@ derive_builder = "0.5"
 log = "0.4"
 tempfile = "3.0"
 indexmap = "1.0"
-
-[features]
-cuda = []

xgboost-sys/Cargo.toml

@@ -15,3 +15,6 @@ libc = "0.2"
 [build-dependencies]
 bindgen = "0.61"
 cmake = "0.1"
+
+[features]
+cuda = []

xgboost-sys/build.rs

@@ -22,6 +22,7 @@ fn main() {
     }
 
     // CMake
+    #[cfg(feature = "cuda")]
     let dst = Config::new(&xgb_root)
         .uses_cxx11()
         .define("BUILD_STATIC_LIB", "ON")
@@ -30,6 +31,12 @@ fn main() {
         .define("BUILD_WITH_CUDA_CUB", "ON")
         .build();
 
+    #[cfg(not(feature = "cuda"))]
+    let dst = Config::new(&xgb_root)
+        .uses_cxx11()
+        .define("BUILD_STATIC_LIB", "ON")
+        .build();
+
     let xgb_root = xgb_root.canonicalize().unwrap();
 
     let bindings = bindgen::Builder::default()