build: enable -Wformat-signedness, fix issues found

Adjust code to avoid `-Wformat-signedness` warnings, while making sure
that enums are always cast to a known type when passing them to `printf`
functions, to support compilers and compiler settings where enums are
not default-size signed ints.

- cast integers printed as hex to `unsigned`. (63 times, 20 of them in
  `mbedtls.c`)
- cast misc enums to `int` for printing. (31 times)
- cast `CURL_LOCK_DATA_*` enums to `int`. (4 times)
- cast `CURL_FORMADD_*` enums to `int`. (13 times)
- cast `CURLSHE_*` enums to `int`. (3 times)
- cast `CURLUE_*` enums to `int`. (33 times)
- cast `CURLMSG_*` enums to `int`. (6 times)
- cast `CURLE_*` enums to `int`. (~380 times)
- unit1675: fix mask.
  Follow-up to 7c34365cce #21879

Ref: #18343 (initial attempt)

Closes #20848

src/tool_main.c

@@ -161,7 +161,7 @@ int main(int argc, char *argv[])
   /* win32_init must be called before other init routines. */
   result = win32_init();
   if(result) {
-    errorf("(%d) Windows-specific init failed", result);
+    errorf("(%d) Windows-specific init failed", (int)result);
     return (int)result;
   }
 #endif

src/tool_operate.c

@@ -616,7 +616,7 @@ static CURLcode post_check_result(struct per_transfer *per, CURLcode result)
   if(!config->synthetic_error && result &&
      (!global->silent || global->showerror)) {
     const char *msg = per->errorbuffer;
-    curl_mfprintf(tool_stderr, "curl: (%d) %s\n", result,
+    curl_mfprintf(tool_stderr, "curl: (%d) %s\n", (int)result,
                   msg[0] ? msg : curl_easy_strerror(result));
     if(result == CURLE_PEER_FAILED_VERIFICATION)
       fputs(CURL_CA_CERT_ERRORMSG, tool_stderr);
@@ -697,7 +697,7 @@ static CURLcode post_close_output(struct per_transfer *per,
     if(!result && rc) {
       /* something went wrong in the writing process */
       result = CURLE_WRITE_ERROR;
-      errorf("curl: (%d) Failed writing body", result);
+      errorf("curl: (%d) Failed writing body", (int)result);
     }
     if(result && config->rm_partial) {
       curlx_struct_stat st;
@@ -856,7 +856,7 @@ static CURLcode append2query(struct OperationConfig *config,
       if(uerr) {
         result = urlerr_cvt(uerr);
         errorf("(%d) Could not parse the URL, "
-               "failed to set query", result);
+               "failed to set query", (int)result);
         config->synthetic_error = TRUE;
       }
       else {

src/tool_ssls.c

@@ -109,7 +109,7 @@ CURLcode tool_ssls_load(struct OperationConfig *config,
     result = curl_easy_ssls_import(easy, NULL, shmac, shmac_len, sdata,
                                    sdata_len);
     if(result) {
-      warnf("import of session from line %d rejected(%d)", i, result);
+      warnf("import of session from line %d rejected(%d)", i, (int)result);
       continue;
     }
     ++imported;
@@ -179,7 +179,7 @@ static CURLcode tool_ssls_exp(CURL *easy, void *userptr,
 out:
   if(result)
     warnf("Warning: error saving SSL session for '%s': %d", session_key,
-          result);
+          (int)result);
   curlx_free(enc);
   return result;
 }

src/tool_urlglob.c

@@ -564,7 +564,7 @@ void glob_show_error(struct URLGlob *glob, const char *url, FILE *error,
     t = glob->error;
 
   /* send error description to the error-stream */
-  curl_mfprintf(error, "curl: (%d) %s\n", result, t);
+  curl_mfprintf(error, "curl: (%d) %s\n", (int)result, t);
 }
 
 CURLcode glob_url(struct URLGlob *glob, const char *url, curl_off_t *urlnum,