Change docs.rs workaround

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cp_sat"
-version = "0.1.3"
+version = "0.2.0"
 edition = "2018"
 description = "Rust bindings to the Google CP-SAT constraint programming solver."
 documentation = "https://docs.rs/cp_sat"
@@ -10,10 +10,6 @@ keywords = ["constraint", "programming", "CP"]
 categories = ["api-bindings", "mathematics", "science"]
 readme = "README.md"
 
-[features]
-# the doc feature will not build C++ wrappers (not needed by the doc)
-doc = []
-
 [dependencies]
 prost = "0.8"
 bytes = "1.1.0"
@@ -22,7 +18,3 @@ libc = "0.2.101"
 [build-dependencies]
 prost-build = { version = "0.8" }
 cc = "1.0"
-
-[package.metadata.docs.rs]
-targets = ["x86_64-unknown-linux-gnu"]
-features = ["doc"]

build.rs

@@ -7,7 +7,7 @@ fn main() {
     )
     .unwrap();
 
-    if !std::env::var("CARGO_FEATURE_DOC").is_ok() {
+    if !std::env::var("DOCS_RS").is_ok() {
         let ortools_prefix = std::env::var("ORTOOLS_PREFIX")
             .ok()
             .unwrap_or("/opt/ortools".into());