diff --git a/src/dc_configure.rs b/src/dc_configure.rs
index acbf8da06..9f3f2c6f8 100644
--- a/src/dc_configure.rs
+++ b/src/dc_configure.rs
@@ -121,10 +121,7 @@ pub unsafe fn dc_stop_ongoing_process(mut context: *mut dc_context_t) {
     };
 }
 // the other dc_job_do_DC_JOB_*() functions are declared static in the c-file
-pub unsafe fn dc_job_do_DC_JOB_CONFIGURE_IMAP(
-    mut context: *mut dc_context_t,
-    mut job: *mut dc_job_t,
-) {
+pub unsafe fn dc_job_do_DC_JOB_CONFIGURE_IMAP(context: *mut dc_context_t, _job: *mut dc_job_t) {
     let mut flags: libc::c_int = 0;
     let mut current_block: u64;
     let mut success: libc::c_int = 0i32;
@@ -1739,9 +1736,9 @@ unsafe fn moz_autoconfigure(
     return moz_ac.out;
 }
 unsafe fn moz_autoconfigure_text_cb(
-    mut userdata: *mut libc::c_void,
-    mut text: *const libc::c_char,
-    mut len: libc::c_int,
+    userdata: *mut libc::c_void,
+    text: *const libc::c_char,
+    _len: libc::c_int,
 ) {
     let mut moz_ac: *mut moz_autoconfigure_t = userdata as *mut moz_autoconfigure_t;
     let mut val: *mut libc::c_char = dc_strdup(text);
@@ -2017,9 +2014,9 @@ unsafe fn outlk_clean_config(mut outlk_ad: *mut outlk_autodiscover_t) {
     }
 }
 unsafe fn outlk_autodiscover_text_cb(
-    mut userdata: *mut libc::c_void,
-    mut text: *const libc::c_char,
-    mut len: libc::c_int,
+    userdata: *mut libc::c_void,
+    text: *const libc::c_char,
+    _len: libc::c_int,
 ) {
     let mut outlk_ad: *mut outlk_autodiscover_t = userdata as *mut outlk_autodiscover_t;
     let mut val: *mut libc::c_char = dc_strdup(text);
@@ -2080,9 +2077,9 @@ unsafe fn outlk_autodiscover_endtag_cb(
     (*outlk_ad).tag_config = 0i32;
 }
 unsafe fn outlk_autodiscover_starttag_cb(
-    mut userdata: *mut libc::c_void,
-    mut tag: *const libc::c_char,
-    mut attr: *mut *mut libc::c_char,
+    userdata: *mut libc::c_void,
+    tag: *const libc::c_char,
+    _attr: *mut *mut libc::c_char,
 ) {
     let mut outlk_ad: *mut outlk_autodiscover_t = userdata as *mut outlk_autodiscover_t;
     if strcmp(tag, b"protocol\x00" as *const u8 as *const libc::c_char) == 0i32 {
diff --git a/src/dc_context.rs b/src/dc_context.rs
index 70b473748..6209ee5c7 100644
--- a/src/dc_context.rs
+++ b/src/dc_context.rs
@@ -282,13 +282,14 @@ unsafe fn cb_get_config(
  * @private @memberof dc_context_t
  */
 unsafe fn cb_dummy(
-    mut context: *mut dc_context_t,
-    mut event: Event,
-    mut data1: uintptr_t,
-    mut data2: uintptr_t,
+    _context: *mut dc_context_t,
+    _event: Event,
+    _data1: uintptr_t,
+    _data2: uintptr_t,
 ) -> uintptr_t {
-    return 0i32 as uintptr_t;
+    0i32 as uintptr_t
 }
+
 pub unsafe fn dc_context_unref(mut context: *mut dc_context_t) {
     if context.is_null() || (*context).magic != 0x11a11807i32 as libc::c_uint {
         return;
@@ -935,9 +936,10 @@ pub unsafe fn dc_search_msgs(
         return 0 as *mut dc_array_t;
     };
 }
+
 pub unsafe fn dc_is_inbox(
-    mut context: *mut dc_context_t,
-    mut folder_name: *const libc::c_char,
+    _context: *mut dc_context_t,
+    folder_name: *const libc::c_char,
 ) -> libc::c_int {
     let mut is_inbox: libc::c_int = 0i32;
     if !folder_name.is_null() {
diff --git a/src/dc_dehtml.rs b/src/dc_dehtml.rs
index 629a0c1a6..3b8c30c7e 100644
--- a/src/dc_dehtml.rs
+++ b/src/dc_dehtml.rs
@@ -63,9 +63,9 @@ pub unsafe fn dc_dehtml(mut buf_terminated: *mut libc::c_char) -> *mut libc::c_c
     };
 }
 unsafe fn dehtml_text_cb(
-    mut userdata: *mut libc::c_void,
-    mut text: *const libc::c_char,
-    mut len: libc::c_int,
+    userdata: *mut libc::c_void,
+    text: *const libc::c_char,
+    _len: libc::c_int,
 ) {
     let mut dehtml: *mut dehtml_t = userdata as *mut dehtml_t;
     if (*dehtml).add_text != 0i32 {
diff --git a/src/dc_hash.rs b/src/dc_hash.rs
index a039b4b0e..ae415e623 100644
--- a/src/dc_hash.rs
+++ b/src/dc_hash.rs
@@ -617,13 +617,13 @@ static mut sjhashUpperToLower: [libc::c_uchar; 256] = [
 ];
 /* Hash and comparison functions when the mode is SJHASH_POINTER
  */
-unsafe fn ptrHash(mut pKey: *const libc::c_void, mut nKey: libc::c_int) -> libc::c_int {
+unsafe fn ptrHash(pKey: *const libc::c_void, _nKey: libc::c_int) -> libc::c_int {
     let mut x: uintptr_t = pKey as uintptr_t;
     return (x ^ x << 8i32 ^ x >> 8i32) as libc::c_int;
 }
 /* Hash and comparison functions when the mode is SJHASH_INT
  */
-unsafe fn intHash(mut pKey: *const libc::c_void, mut nKey: libc::c_int) -> libc::c_int {
+unsafe fn intHash(_pKey: *const libc::c_void, mut nKey: libc::c_int) -> libc::c_int {
     return nKey ^ nKey << 8i32 ^ nKey >> 8i32;
 }
 /*
@@ -796,10 +796,10 @@ unsafe fn sjhashStrNICmp(
     };
 }
 unsafe fn ptrCompare(
-    mut pKey1: *const libc::c_void,
-    mut n1: libc::c_int,
-    mut pKey2: *const libc::c_void,
-    mut n2: libc::c_int,
+    pKey1: *const libc::c_void,
+    _n1: libc::c_int,
+    pKey2: *const libc::c_void,
+    _n2: libc::c_int,
 ) -> libc::c_int {
     if pKey1 == pKey2 {
         return 0i32;
@@ -809,14 +809,16 @@ unsafe fn ptrCompare(
     }
     return 1i32;
 }
+
 unsafe fn intCompare(
-    mut pKey1: *const libc::c_void,
-    mut n1: libc::c_int,
-    mut pKey2: *const libc::c_void,
-    mut n2: libc::c_int,
+    _pKey1: *const libc::c_void,
+    n1: libc::c_int,
+    _pKey2: *const libc::c_void,
+    n2: libc::c_int,
 ) -> libc::c_int {
     return n2 - n1;
 }
+
 pub unsafe fn dc_hash_find(
     mut pH: *const dc_hash_t,
     mut pKey: *const libc::c_void,
diff --git a/src/dc_imap.rs b/src/dc_imap.rs
index cb0242b7f..b8df44e4c 100644
--- a/src/dc_imap.rs
+++ b/src/dc_imap.rs
@@ -1468,7 +1468,6 @@ unsafe fn add_flag(
     mut server_uid: uint32_t,
     mut flag: *mut mailimap_flag,
 ) -> libc::c_int {
-    let mut r: libc::c_int = 0i32;
     let mut flag_list: *mut mailimap_flag_list = 0 as *mut mailimap_flag_list;
     let mut store_att_flags: *mut mailimap_store_att_flags = 0 as *mut mailimap_store_att_flags;
     let mut set: *mut mailimap_set = mailimap_set_new_single(server_uid);
@@ -1476,8 +1475,7 @@ unsafe fn add_flag(
         flag_list = mailimap_flag_list_new_empty();
         mailimap_flag_list_add(flag_list, flag);
         store_att_flags = mailimap_store_att_flags_new_add_flags(flag_list);
-        r = mailimap_uid_store((*imap).etpan, set, store_att_flags);
-        0 != dc_imap_is_error(imap, r);
+        mailimap_uid_store((*imap).etpan, set, store_att_flags);
     }
     if !store_att_flags.is_null() {
         mailimap_store_att_flags_free(store_att_flags);
@@ -1486,11 +1484,11 @@ unsafe fn add_flag(
         mailimap_set_free(set);
         set = 0 as *mut mailimap_set
     }
-    return if 0 != (*imap).should_reconnect {
+    if 0 != (*imap).should_reconnect {
         0i32
     } else {
         1i32
-    };
+    }
 }
 pub unsafe fn dc_imap_set_seen(
     mut imap: *mut dc_imap_t,
diff --git a/src/dc_imex.rs b/src/dc_imex.rs
index 9325c9be5..3ce712b5d 100644
--- a/src/dc_imex.rs
+++ b/src/dc_imex.rs
@@ -343,7 +343,7 @@ pub unsafe extern "C" fn dc_render_setup_file(
     free(self_addr as *mut libc::c_void);
     return ret_setupfilecontent;
 }
-pub unsafe fn dc_create_setup_code(mut context: *mut dc_context_t) -> *mut libc::c_char {
+pub unsafe fn dc_create_setup_code(_context: *mut dc_context_t) -> *mut libc::c_char {
     let mut random_val: uint16_t = 0i32 as uint16_t;
     let mut i: libc::c_int = 0i32;
     let mut ret: dc_strbuilder_t = dc_strbuilder_t {
@@ -639,8 +639,8 @@ pub unsafe fn dc_decrypt_setup_file(
     return payload;
 }
 pub unsafe fn dc_normalize_setup_code(
-    mut context: *mut dc_context_t,
-    mut in_0: *const libc::c_char,
+    _context: *mut dc_context_t,
+    in_0: *const libc::c_char,
 ) -> *mut libc::c_char {
     if in_0.is_null() {
         return 0 as *mut libc::c_char;
diff --git a/src/dc_keyhistory.rs b/src/dc_keyhistory.rs
index 07e596ad0..0aabaff0f 100644
--- a/src/dc_keyhistory.rs
+++ b/src/dc_keyhistory.rs
@@ -10,11 +10,11 @@ use crate::x::*;
 /* yes: uppercase */
 /* library private: key-history */
 pub unsafe fn dc_add_to_keyhistory(
-    mut context: *mut dc_context_t,
-    mut rfc724_mid: *const libc::c_char,
-    mut sending_time: time_t,
-    mut addr: *const libc::c_char,
-    mut fingerprint: *const libc::c_char,
+    _context: *mut dc_context_t,
+    _rfc724_mid: *const libc::c_char,
+    _sending_time: time_t,
+    _addr: *const libc::c_char,
+    _fingerprint: *const libc::c_char,
 ) {
 
 }
diff --git a/src/dc_location.rs b/src/dc_location.rs
index b165cac02..4eb2df163 100644
--- a/src/dc_location.rs
+++ b/src/dc_location.rs
@@ -625,11 +625,7 @@ pub unsafe fn dc_kml_parse(
     free(content_nullterminated as *mut libc::c_void);
     return kml;
 }
-unsafe fn kml_text_cb(
-    mut userdata: *mut libc::c_void,
-    mut text: *const libc::c_char,
-    mut len: libc::c_int,
-) {
+unsafe fn kml_text_cb(userdata: *mut libc::c_void, text: *const libc::c_char, _len: libc::c_int) {
     let mut kml: *mut dc_kml_t = userdata as *mut dc_kml_t;
     if 0 != (*kml).tag & (0x4i32 | 0x10i32) {
         let mut val: *mut libc::c_char = dc_strdup(text);
@@ -776,8 +772,8 @@ pub unsafe fn dc_kml_unref(mut kml: *mut dc_kml_t) {
     free(kml as *mut libc::c_void);
 }
 pub unsafe fn dc_job_do_DC_JOB_MAYBE_SEND_LOCATIONS(
-    mut context: *mut dc_context_t,
-    mut job: *mut dc_job_t,
+    context: *mut dc_context_t,
+    _job: *mut dc_job_t,
 ) {
     let mut stmt_chats: *mut sqlite3_stmt = 0 as *mut sqlite3_stmt;
     let mut stmt_locations: *mut sqlite3_stmt = 0 as *mut sqlite3_stmt;
diff --git a/src/dc_mimeparser.rs b/src/dc_mimeparser.rs
index 68b7ce3b6..3bf5e86f9 100644
--- a/src/dc_mimeparser.rs
+++ b/src/dc_mimeparser.rs
@@ -826,9 +826,9 @@ unsafe fn dc_mimeparser_parse_mime_recursive(
     return any_part_added;
 }
 unsafe fn hash_header(
-    mut out: *mut dc_hash_t,
-    mut in_0: *const mailimf_fields,
-    mut context: *mut dc_context_t,
+    out: *mut dc_hash_t,
+    in_0: *const mailimf_fields,
+    _context: *mut dc_context_t,
 ) {
     if in_0.is_null() {
         return;
diff --git a/src/dc_pgp.rs b/src/dc_pgp.rs
index 83eacce64..0993f98d8 100644
--- a/src/dc_pgp.rs
+++ b/src/dc_pgp.rs
@@ -19,11 +19,12 @@ use crate::x::*;
 pub unsafe fn dc_pgp_init() {}
 pub unsafe fn dc_pgp_exit() {}
 pub unsafe fn dc_pgp_rand_seed(
-    mut context: *mut dc_context_t,
-    mut buf: *const libc::c_void,
-    mut bytes: size_t,
+    _context: *mut dc_context_t,
+    _buf: *const libc::c_void,
+    _bytes: size_t,
 ) {
 }
+
 pub unsafe fn dc_split_armored_data(
     mut buf: *mut libc::c_char,
     mut ret_headerline: *mut *const libc::c_char,
diff --git a/src/dc_saxparser.rs b/src/dc_saxparser.rs
index 56b12d175..38c6058c1 100644
--- a/src/dc_saxparser.rs
+++ b/src/dc_saxparser.rs
@@ -36,22 +36,21 @@ pub unsafe extern "C" fn dc_saxparser_init(
     (*saxparser).endtag_cb = Some(def_endtag_cb);
     (*saxparser).text_cb = Some(def_text_cb);
 }
-unsafe fn def_text_cb(
-    mut userdata: *mut libc::c_void,
-    mut text: *const libc::c_char,
-    mut len: libc::c_int,
-) {
+unsafe fn def_text_cb(_userdata: *mut libc::c_void, _text: *const libc::c_char, _len: libc::c_int) {
 }
-unsafe fn def_endtag_cb(mut userdata: *mut libc::c_void, mut tag: *const libc::c_char) {}
+
+unsafe fn def_endtag_cb(_userdata: *mut libc::c_void, _tag: *const libc::c_char) {}
+
 /* ******************************************************************************
  * Tools
  ******************************************************************************/
 unsafe fn def_starttag_cb(
-    mut userdata: *mut libc::c_void,
-    mut tag: *const libc::c_char,
-    mut attr: *mut *mut libc::c_char,
+    _userdata: *mut libc::c_void,
+    _tag: *const libc::c_char,
+    _attr: *mut *mut libc::c_char,
 ) {
 }
+
 pub unsafe fn dc_saxparser_set_tag_handler(
     mut saxparser: *mut dc_saxparser_t,
     mut starttag_cb: dc_saxparser_starttag_cb_t,
diff --git a/src/dc_smtp.rs b/src/dc_smtp.rs
index 5ad88e412..f76b63ed8 100644
--- a/src/dc_smtp.rs
+++ b/src/dc_smtp.rs
@@ -388,11 +388,12 @@ pub unsafe fn dc_smtp_connect(
     return success;
 }
 unsafe extern "C" fn body_progress(
-    mut current: size_t,
-    mut maximum: size_t,
-    mut user_data: *mut libc::c_void,
+    _current: size_t,
+    _maximum: size_t,
+    _user_data: *mut libc::c_void,
 ) {
 }
+
 pub unsafe fn dc_smtp_send_msg(
     mut smtp: *mut dc_smtp_t,
     mut recipients: *const clist,
diff --git a/src/dc_sqlite3.rs b/src/dc_sqlite3.rs
index 49f6fd384..b8b67c471 100644
--- a/src/dc_sqlite3.rs
+++ b/src/dc_sqlite3.rs
@@ -1220,9 +1220,13 @@ pub unsafe fn dc_sqlite3_get_rowid2(
     sqlite3_free(q3 as *mut libc::c_void);
     return id;
 }
-pub unsafe fn dc_sqlite3_begin_transaction(mut sql: *mut dc_sqlite3_t) {}
-pub unsafe fn dc_sqlite3_commit(mut sql: *mut dc_sqlite3_t) {}
-pub unsafe fn dc_sqlite3_rollback(mut sql: *mut dc_sqlite3_t) {}
+
+// NOTE: This assumes no transaction usage, port code if this is desired.
+
+pub unsafe fn dc_sqlite3_begin_transaction(_sql: *mut dc_sqlite3_t) {}
+pub unsafe fn dc_sqlite3_commit(_sql: *mut dc_sqlite3_t) {}
+pub unsafe fn dc_sqlite3_rollback(_sql: *mut dc_sqlite3_t) {}
+
 /* housekeeping */
 pub unsafe fn dc_housekeeping(mut context: *mut dc_context_t) {
     let mut keep_files_newer_than: time_t = 0;
diff --git a/src/dc_strencode.rs b/src/dc_strencode.rs
index 0f25ff490..c56f07108 100644
--- a/src/dc_strencode.rs
+++ b/src/dc_strencode.rs
@@ -246,7 +246,7 @@ unsafe fn quote_word(
     let mut cur: *const libc::c_char = 0 as *const libc::c_char;
     let mut i: size_t = 0i32 as size_t;
     let mut hex: [libc::c_char; 4] = [0; 4];
-    let mut col: libc::c_int = 0i32;
+    // let mut col: libc::c_int = 0i32;
     if mmap_string_append(mmapstr, b"=?\x00" as *const u8 as *const libc::c_char).is_null() {
         return 0i32;
     }
@@ -256,7 +256,7 @@ unsafe fn quote_word(
     if mmap_string_append(mmapstr, b"?Q?\x00" as *const u8 as *const libc::c_char).is_null() {
         return 0i32;
     }
-    col = (*mmapstr).len as libc::c_int;
+    // col = (*mmapstr).len as libc::c_int;
     cur = word;
     i = 0i32 as size_t;
     while i < size {
@@ -281,7 +281,7 @@ unsafe fn quote_word(
             if mmap_string_append(mmapstr, hex.as_mut_ptr()).is_null() {
                 return 0i32;
             }
-            col += 3i32
+        // col += 3i32
         } else {
             if *cur as libc::c_int == ' ' as i32 {
                 if mmap_string_append_c(mmapstr, '_' as i32 as libc::c_char).is_null() {
@@ -290,7 +290,7 @@ unsafe fn quote_word(
             } else if mmap_string_append_c(mmapstr, *cur).is_null() {
                 return 0i32;
             }
-            col += 3i32
+            // col += 3i32
         }
         cur = cur.offset(1isize);
         i = i.wrapping_add(1)
diff --git a/src/types.rs b/src/types.rs
index 68635bc46..0cef98fd0 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -1190,14 +1190,14 @@ pub struct _RuneLocale {
     pub __magic: [libc::c_char; 8],
     pub __encoding: [libc::c_char; 32],
     pub __sgetrune: Option<
-        unsafe fn(
+        unsafe extern "C" fn(
             _: *const libc::c_char,
             _: __darwin_size_t,
             _: *mut *const libc::c_char,
         ) -> __darwin_rune_t,
     >,
     pub __sputrune: Option<
-        unsafe fn(
+        unsafe extern "C" fn(
             _: __darwin_rune_t,
             _: *mut libc::c_char,
             _: __darwin_size_t,