diff --git a/libc-test/build.rs b/libc-test/build.rs
index 226757c6ad8dc..8221e48aa94de 100644
--- a/libc-test/build.rs
+++ b/libc-test/build.rs
@@ -2448,6 +2448,7 @@ fn test_emscripten(target: &str) {
 
     let mut cfg = ctest_cfg();
     cfg.define("_GNU_SOURCE", None); // FIXME: ??
+    cfg.flag("-pthread"); // Enable POSIX threads support.
 
     headers! { cfg:
                "aio.h",
diff --git a/src/unix/linux_like/emscripten/mod.rs b/src/unix/linux_like/emscripten/mod.rs
index 5494aad378cf2..db00f564ea729 100644
--- a/src/unix/linux_like/emscripten/mod.rs
+++ b/src/unix/linux_like/emscripten/mod.rs
@@ -1879,6 +1879,16 @@ extern "C" {
         f: extern "C" fn(*mut ::c_void) -> *mut ::c_void,
         value: *mut ::c_void,
     ) -> ::c_int;
+    pub fn pthread_setschedparam(
+        native: ::pthread_t,
+        policy: ::c_int,
+        param: *const ::sched_param,
+    ) -> ::c_int;
+    pub fn pthread_getschedparam(
+        native: ::pthread_t,
+        policy: *mut ::c_int,
+        param: *mut ::sched_param,
+    ) -> ::c_int;
 }
 
 cfg_if! {