grpc-sys: Use grpc headers found by pkgconfig.

Previously the bundled grpc headers were always used to generate
bindings even in the case where pkgconfig was used to locate gRPC to
link against. This caused errors at runtime, e.g., SEGFAULT, rather than
a compile-time error. To fix this, use the headers found by pkgconfig to
generate bindings rather than than the bundled headers if pkgconfig is
already being used.

Signed-off-by: Steven Sloboda <ssloboda@starry.com>

grpc-sys/build.rs

@@ -268,7 +268,7 @@ fn get_env(name: &str) -> Option<String> {
 // Generate the bindings to grpc C-core.
 // Try to disable the generation of platform-related bindings.
 #[cfg(feature = "use-bindgen")]
-fn bindgen_grpc(file_path: &PathBuf) {
+fn bindgen_grpc(file_path: &PathBuf, grpc_include_dir: &PathBuf) {
     // create a config to generate binding file
     let mut config = bindgen::Builder::default();
     if cfg!(feature = "secure") {
@@ -281,7 +281,7 @@ fn bindgen_grpc(file_path: &PathBuf) {
 
     // Search header files with API interface
     let mut headers = Vec::new();
-    for result in WalkDir::new(Path::new("./grpc/include")) {
+    for result in WalkDir::new(grpc_include_dir) {
         let dent = result.expect("Error happened when search headers");
         if !dent.file_type().is_file() {
             continue;
@@ -307,7 +307,7 @@ fn bindgen_grpc(file_path: &PathBuf) {
     let cfg = config
         .header("grpc_wrap.cc")
         .clang_arg("-xc++")
-        .clang_arg("-I./grpc/include")
+        .clang_arg(format!("-I{}", grpc_include_dir.display()))
         .clang_arg("-std=c++11")
         .rustfmt_bindings(true)
         .impl_debug(true)
@@ -344,7 +344,7 @@ fn bindgen_grpc(file_path: &PathBuf) {
 // Determine if need to update bindings. Supported platforms do not
 // need to be updated by default unless the UPDATE_BIND is specified.
 // Other platforms use bindgen to generate the bindings every time.
-fn config_binding_path() {
+fn config_binding_path(#[allow(unused_variables)] grpc_include_dir: &PathBuf) {
     let target = env::var("TARGET").unwrap();
     let file_path: PathBuf = match target.as_str() {
         "x86_64-unknown-linux-gnu" | "aarch64-unknown-linux-gnu" => {
@@ -359,7 +359,7 @@ fn config_binding_path() {
 
             #[cfg(feature = "use-bindgen")]
             if env::var("UPDATE_BIND").is_ok() {
-                bindgen_grpc(&file_path);
+                bindgen_grpc(&file_path, grpc_include_dir);
             }
 
             file_path
@@ -368,7 +368,7 @@ fn config_binding_path() {
             let file_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("grpc-bindings.rs");
 
             #[cfg(feature = "use-bindgen")]
-            bindgen_grpc(&file_path);
+            bindgen_grpc(&file_path, grpc_include_dir);
 
             file_path
         }
@@ -400,15 +400,28 @@ fn main() {
         cc.define("_WIN32_WINNT", Some("0x600"));
     }
 
-    if get_env("GRPCIO_SYS_USE_PKG_CONFIG").map_or(false, |s| s == "1") {
+    let grpc_include_dir = if get_env("GRPCIO_SYS_USE_PKG_CONFIG").map_or(false, |s| s == "1") {
         // Print cargo metadata.
         let lib_core = probe_library(library, true);
+        let grpc_include_dir = lib_core
+            .include_paths
+            .iter()
+            .map(|inc_path| inc_path.join("grpc"))
+            .find(|grpc_inc_path| grpc_inc_path.is_dir())
+            .unwrap_or_else(|| {
+                panic!(
+                    "Could not find grpc include dir in {:#?}",
+                    lib_core.include_paths
+                )
+            });
         for inc_path in lib_core.include_paths {
             cc.include(inc_path);
         }
+        grpc_include_dir
     } else {
         build_grpc(&mut cc, library);
-    }
+        "./grpc/include".into()
+    };
 
     cc.cpp(true);
     if !cfg!(target_env = "msvc") {
@@ -418,5 +431,5 @@ fn main() {
     cc.warnings_into_errors(true);
     cc.compile("libgrpc_wrap.a");
 
-    config_binding_path();
+    config_binding_path(&grpc_include_dir);
 }