diff --git a/src/libprofiler_builtins/build.rs b/src/libprofiler_builtins/build.rs
index 6c7407760df..8d6c7d68dfe 100644
--- a/src/libprofiler_builtins/build.rs
+++ b/src/libprofiler_builtins/build.rs
@@ -43,6 +43,8 @@ fn main() {
         cfg.define("strdup", Some("_strdup"));
         cfg.define("open", Some("_open"));
         cfg.define("fdopen", Some("_fdopen"));
+        cfg.define("getpid", Some("_getpid"));
+        cfg.define("fileno", Some("_fileno"));
     } else {
         // Turn off various features of gcc and such, mostly copying
         // compiler-rt's build system already