Bug 1751331 - Use the mozbuild crate in servo. r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D136562

Cargo.lock

@@ -4830,6 +4830,7 @@ dependencies = [
  "malloc_size_of",
  "malloc_size_of_derive",
  "matches",
+ "mozbuild",
  "new_debug_unreachable",
  "nsstring",
  "num-derive",

servo/components/style/Cargo.toml

@@ -17,7 +17,7 @@ path = "lib.rs"
 doctest = false
 
 [features]
-gecko = ["nsstring", "serde", "style_traits/gecko", "bindgen", "regex", "toml"]
+gecko = ["nsstring", "serde", "style_traits/gecko", "bindgen", "regex", "toml", "mozbuild"]
 servo = ["serde", "style_traits/servo", "servo_atoms", "servo_config", "html5ever",
          "cssparser/serde", "encoding_rs", "malloc_size_of/servo", "arrayvec/use_union",
          "servo_url", "string_cache", "to_shmem/servo", "servo_arc/servo"]
@@ -84,3 +84,4 @@ bindgen = {version = "0.56", optional = true, default-features = false}
 regex = {version = "1.0", optional = true, default-features = false, features = ["perf", "std"]}
 walkdir = "2.1.4"
 toml = {version = "0.4.5", optional = true, default-features = false}
+mozbuild = {version = "0.1", optional = true}

servo/components/style/build_gecko.rs

@@ -42,14 +42,12 @@ fn read_config(path: &PathBuf) -> Table {
 lazy_static! {
     static ref CONFIG: Table = {
         // Load Gecko's binding generator config from the source tree.
-        let path = PathBuf::from(env::var_os("MOZ_SRC").unwrap())
-            .join("layout/style/ServoBindings.toml");
+        let path = mozbuild::TOPSRCDIR.join("layout/style/ServoBindings.toml");
         read_config(&path)
     };
     static ref BINDGEN_FLAGS: Vec<String> = {
         // Load build-specific config overrides.
-        let path = PathBuf::from(env::var_os("MOZ_TOPOBJDIR").unwrap())
-            .join("layout/style/extra-bindgen-flags");
+        let path = mozbuild::TOPOBJDIR.join("layout/style/extra-bindgen-flags");
         println!("cargo:rerun-if-changed={}", path.to_str().unwrap());
         fs::read_to_string(path).expect("Failed to read extra-bindgen-flags file")
             .split_whitespace()
@@ -57,13 +55,7 @@ lazy_static! {
             .collect()
     };
     static ref INCLUDE_RE: Regex = Regex::new(r#"#include\s*"(.+?)""#).unwrap();
-    static ref DISTDIR_PATH: PathBuf = {
-        let path = PathBuf::from(env::var_os("MOZ_TOPOBJDIR").unwrap());
-        if !path.is_absolute() || !path.is_dir() {
-            panic!("MOZ_TOPOBJDIR must be an absolute directory, was: {}", path.display());
-        }
-        path.join("dist")
-    };
+    static ref DISTDIR_PATH: PathBuf = mozbuild::TOPOBJDIR.join("dist");
     static ref SEARCH_PATHS: Vec<PathBuf> = vec![
         DISTDIR_PATH.join("include"),
         DISTDIR_PATH.join("include/nspr"),