diff --git a/src/x.rs b/src/x.rs
index f78c8f091..78e0d6685 100644
--- a/src/x.rs
+++ b/src/x.rs
@@ -486,12 +486,20 @@ extern "C" {
         _: *mut *mut libc::c_char,
         _: libc::c_int,
     ) -> libc::c_long;
+    #[cfg(target_os = "macos")]
     pub fn __assert_rtn(
         _: *const libc::c_char,
         _: *const libc::c_char,
         _: libc::c_int,
         _: *const libc::c_char,
     ) -> !;
+    #[cfg(not(target_os = "macos"))]
+    fn __assert(
+        _: *const libc::c_char,
+        _: *const libc::c_char,
+        _: libc::c_int,
+        _: *const libc::c_char,
+    ) -> !;
 
     pub fn carray_delete_slow(array: *mut carray, indx: libc::c_uint) -> libc::c_int;
     pub fn mailimf_msg_id_parse(
@@ -642,3 +650,13 @@ extern "C" {
     pub fn dc_strbuilder_catf(_: *mut dc_strbuilder_t, format: *const libc::c_char, _: ...);
     pub fn dc_mprintf(format: *const libc::c_char, _: ...) -> *mut libc::c_char;
 }
+
+#[cfg(not(target_os = "macos"))]
+pub unsafe extern "C" fn __assert_rtn(
+    a: *const libc::c_char,
+    b: *const libc::c_char,
+    c: libc::c_int,
+    d: *const libc::c_char,
+) -> ! {
+    __assert(a, b, c, d)
+}