diff --git a/src/dc_strbuilder.rs b/src/dc_strbuilder.rs
index 4b3834d52..1ad2e7a62 100644
--- a/src/dc_strbuilder.rs
+++ b/src/dc_strbuilder.rs
@@ -33,7 +33,6 @@ pub unsafe extern "C" fn dc_strbuilder_init(
     (*strbuilder).free = (*strbuilder).allocated - 1i32;
     (*strbuilder).eos = (*strbuilder).buf;
 }
-#[no_mangle]
 pub unsafe extern "C" fn dc_strbuilder_cat(
     mut strbuilder: *mut dc_strbuilder_t,
     mut text: *const libc::c_char,
diff --git a/src/dc_tools.rs b/src/dc_tools.rs
index 0289c7e4d..a7bb27a0a 100644
--- a/src/dc_tools.rs
+++ b/src/dc_tools.rs
@@ -19,7 +19,6 @@ pub unsafe extern "C" fn dc_exactly_one_bit_set(mut v: libc::c_int) -> libc::c_i
 }
 /* string tools */
 /* dc_strdup() returns empty string if NULL is given, never returns NULL (exits on errors) */
-#[no_mangle]
 pub unsafe extern "C" fn dc_strdup(mut s: *const libc::c_char) -> *mut libc::c_char {
     let mut ret: *mut libc::c_char = 0 as *mut libc::c_char;
     if !s.is_null() {