rust: fix build on nixos

Running into these issues: rust-lang/rust-bindgen#687

Signed-off-by: William Casarin <[email protected]>

Author: jb55

build.rs

@@ -3,8 +3,20 @@ extern crate bindgen;
 use std::env;
 use std::path::PathBuf;
 
-fn main() {
+#[derive(Debug)]
+struct IgnoreMacros(String);
+
+impl bindgen::callbacks::ParseCallbacks for IgnoreMacros {
+    fn will_parse_macro(&self, name: &str) -> bindgen::callbacks::MacroParsingBehavior {
+        if name == self.0 {
+            bindgen::callbacks::MacroParsingBehavior::Ignore
+        } else {
+            bindgen::callbacks::MacroParsingBehavior::Default
+        }
+    }
+}
 
+fn main() {
     // Tell cargo to look for shared libraries in the specified directory
     let lib_path = PathBuf::from(env::current_dir().unwrap());
     println!("cargo:rustc-link-search={}", lib_path.display());
@@ -14,6 +26,8 @@ fn main() {
     println!("cargo:rustc-link-lib=secp256k1");
     println!("cargo:rustc-link-lib=sodium");
 
+    let ignored_macros = IgnoreMacros("IPPORT_RESERVED".to_string());
+
     // The bindgen::Builder is the main entry point
     // to bindgen, and lets you build up options for
     // the resulting bindings.
@@ -25,6 +39,7 @@ fn main() {
         .clang_arg("-Ideps/secp256k1/include")
         .clang_arg("-Ideps/libsodium/src/libsodium/include")
         .header("deps/secp256k1/include/secp256k1.h")
+        .parse_callbacks(Box::new(ignored_macros))
         .trust_clang_mangling(false)
         // Finish the builder and generate the bindings.
         .generate()