feat(sys): make deps required for building Nginx optional

These dependencies are not necessary when using a prebuilt Nginx tree.

Author: bavshin-f5

Cargo.toml

@@ -21,6 +21,9 @@ keywords = ["nginx", "module", "sys"]
 [dependencies]
 nginx-sys = { path = "nginx-sys", version = "0.5.0"}
 
+[features]
+default = ["nginx-sys/vendored"]
+
 [badges]
 maintenance = { status = "experimental" }
 

nginx-sys/Cargo.toml

@@ -17,8 +17,11 @@ crate-type = ["staticlib", "rlib"]
 
 [build-dependencies]
 bindgen = "0.69.4"
-which = "6.0.0"
-duct = "0.13.7"
-ureq = { version = "2.9.6", features = ["tls"] }
-flate2 = "1.0.28"
-tar = "0.4.40"
+duct = { version = "0.13.7", optional = true }
+flate2 = { version = "1.0.28", optional = true }
+tar =  { version = "0.4.40", optional = true }
+ureq = { version = "2.9.6", features = ["tls"], optional = true }
+which = { version = "6.0.0", optional = true }
+
+[features]
+vendored = ["dep:which", "dep:duct", "dep:ureq", "dep:flate2", "dep:tar"]

nginx-sys/build/main.rs

@@ -5,6 +5,7 @@ use std::error::Error as StdError;
 use std::fs::read_to_string;
 use std::path::PathBuf;
 
+#[cfg(feature = "vendored")]
 mod vendored;
 
 const ENV_VARS_TRIGGERING_RECOMPILE: [&str; 2] = ["OUT_DIR", "NGX_OBJS"];
@@ -14,10 +15,12 @@ const ENV_VARS_TRIGGERING_RECOMPILE: [&str; 2] = ["OUT_DIR", "NGX_OBJS"];
 /// extract them, execute autoconf `configure` for NGINX, compile NGINX and finally install
 /// NGINX in a subdirectory with the project.
 fn main() -> Result<(), Box<dyn StdError>> {
-    let nginx_build_dir = if let Ok(v) = env::var("NGX_OBJS") {
-        PathBuf::from(v).canonicalize()?
-    } else {
-        vendored::build()?
+    let nginx_build_dir = match std::env::var("NGX_OBJS") {
+        Ok(v) => PathBuf::from(v).canonicalize()?,
+        #[cfg(feature = "vendored")]
+        Err(_) => vendored::build()?,
+        #[cfg(not(feature = "vendored"))]
+        Err(_) => panic!("\"nginx-sys/vendored\" feature is disabled and NGX_OBJS is not specified"),
     };
     // Hint cargo to rebuild if any of the these environment variables values change
     // because they will trigger a recompilation of NGINX with different parameters