Set C++ std in cxx_build for simpler usage

BUILD

@@ -50,6 +50,11 @@ rust_library(
     ],
 )
 
+rust_library(
+    name = "cxxbridge-flags",
+    srcs = glob(["flags/src/**"]),
+)
+
 rust_library(
     name = "build",
     srcs = glob(["gen/build/src/**/*.rs"]),
@@ -61,6 +66,7 @@ rust_library(
         "//third-party:proc-macro2",
         "//third-party:quote",
         "//third-party:syn",
+        "//:cxxbridge-flags",
     ],
 )
 

demo/Cargo.toml

@@ -10,5 +10,4 @@ cxx = { path = "..", features= ["c++14"] }
 
 [build-dependencies]
 cxx-build = { path = "../gen/build" }
-cxxbridge-flags = { path = "../flags" }
 

demo/build.rs

@@ -1,7 +1,6 @@
 fn main() {
     cxx_build::bridge("src/main.rs")
         .file("src/demo.cc")
-        .flag_if_supported(cxxbridge_flags::STD)
         .compile("cxxbridge-demo");
 
     println!("cargo:rerun-if-changed=src/main.rs");

gen/build/Cargo.toml

@@ -16,6 +16,7 @@ codespan-reporting = "0.9"
 proc-macro2 = { version = "1.0.17", default-features = false, features = ["span-locations"] }
 quote = { version = "1.0", default-features = false }
 syn = { version = "1.0.20", default-features = false, features = ["parsing", "printing", "clone-impls", "full"] }
+cxxbridge-flags = { version = "=0.4.7", path = "../../flags", default-features = false }
 
 [dev-dependencies]
 cxx-gen = { version = "0.4", path = "../lib" }

gen/build/src/lib.rs

@@ -134,6 +134,8 @@ fn build(rust_source_files: &mut dyn Iterator<Item = impl AsRef<Path>>) -> Resul
     build.cpp(true);
     build.cpp_link_stdlib(None); // linked via link-cplusplus crate
     build.include(&include_dir);
+    // Set feature parameters, such as C++ std, for simpler usage
+    build.flag_if_supported(cxxbridge_flags::STD);
     write_header(prj);
     let crate_dir = symlink_crate(prj, &mut build);
 

tests/ffi/Cargo.toml

@@ -12,4 +12,3 @@ cxx = { path = "../.." }
 
 [build-dependencies]
 cxx-build = { path = "../../gen/build" }
-cxxbridge-flags = { path = "../../flags" }

tests/ffi/build.rs

@@ -6,6 +6,5 @@ fn main() {
     let sources = vec!["lib.rs", "module.rs"];
     cxx_build::bridges(sources)
         .file("tests.cc")
-        .flag_if_supported(cxxbridge_flags::STD)
         .compile("cxx-test-suite");
 }