build: delete/replace clang warning pragmas

- delete redundant warning suppressions for `-Wformat-nonliteral`.
  This now relies on `CURL_PRINTF()` and it's theoratically possible
  that this macro isn't active but the warning is. We're ignoring this
  as a corner-case here.

- replace two pragmas with code changes to avoid the warnings.

Follow-up to aee4ebe591 #12803
Follow-up to 0923012758 #12540
Follow-up to 3829759bd0 #12489

Reviewed-by: Daniel Stenberg
Closes #12812

lib/curl_trc.c

@@ -92,14 +92,7 @@ void Curl_failf(struct Curl_easy *data, const char *fmt, ...)
     int len;
     char error[CURL_ERROR_SIZE + 2];
     va_start(ap, fmt);
-#ifdef __clang__
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wformat-nonliteral"
-#endif
     len = mvsnprintf(error, CURL_ERROR_SIZE, fmt, ap);
-#ifdef __clang__
-#pragma clang diagnostic pop
-#endif
 
     if(data->set.errorbuffer && !data->state.errorbuf) {
       strcpy(data->set.errorbuffer, error);
@@ -125,14 +118,7 @@ void Curl_infof(struct Curl_easy *data, const char *fmt, ...)
     int len;
     char buffer[MAXINFO + 2];
     va_start(ap, fmt);
-#ifdef __clang__
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wformat-nonliteral"
-#endif
     len = mvsnprintf(buffer, MAXINFO, fmt, ap);
-#ifdef __clang__
-#pragma clang diagnostic pop
-#endif
     va_end(ap);
     buffer[len++] = '\n';
     buffer[len] = '\0';
@@ -150,14 +136,7 @@ void Curl_trc_cf_infof(struct Curl_easy *data, struct Curl_cfilter *cf,
     char buffer[MAXINFO + 2];
     len = msnprintf(buffer, MAXINFO, "[%s] ", cf->cft->name);
     va_start(ap, fmt);
-#ifdef __clang__
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wformat-nonliteral"
-#endif
     len += mvsnprintf(buffer + len, MAXINFO - len, fmt, ap);
-#ifdef __clang__
-#pragma clang diagnostic pop
-#endif
     va_end(ap);
     buffer[len++] = '\n';
     buffer[len] = '\0';

lib/dict.c

@@ -135,14 +135,7 @@ static CURLcode sendf(curl_socket_t sockfd, struct Curl_easy *data,
   char *sptr;
   va_list ap;
   va_start(ap, fmt);
-#ifdef __clang__
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wformat-nonliteral"
-#endif
   s = vaprintf(fmt, ap); /* returns an allocated string */
-#ifdef __clang__
-#pragma clang diagnostic pop
-#endif
   va_end(ap);
   if(!s)
     return CURLE_OUT_OF_MEMORY; /* failure */

lib/dynbuf.c

@@ -204,14 +204,7 @@ CURLcode Curl_dyn_vaddf(struct dynbuf *s, const char *fmt, va_list ap)
   return CURLE_OUT_OF_MEMORY;
 #else
   char *str;
-#ifdef __clang__
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wformat-nonliteral"
-#endif
   str = vaprintf(fmt, ap); /* this allocs a new string to append */
-#ifdef __clang__
-#pragma clang diagnostic pop
-#endif
 
   if(str) {
     CURLcode result = dyn_nappend(s, (unsigned char *)str, strlen(str));

lib/memdebug.c

@@ -448,14 +448,7 @@ void curl_dbg_log(const char *format, ...)
     return;
 
   va_start(ap, format);
-#ifdef __clang__
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wformat-nonliteral"
-#endif
   nchars = mvsnprintf(buf, LOGLINE_BUFSIZE, format, ap);
-#ifdef __clang__
-#pragma clang diagnostic pop
-#endif
   va_end(ap);
 
   if(nchars > LOGLINE_BUFSIZE - 1)

lib/mime.c

@@ -1677,14 +1677,7 @@ CURLcode Curl_mime_add_header(struct curl_slist **slp, const char *fmt, ...)
   va_list ap;
 
   va_start(ap, fmt);
-#ifdef __clang__
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wformat-nonliteral"
-#endif
   s = curl_mvaprintf(fmt, ap);
-#ifdef __clang__
-#pragma clang diagnostic pop
-#endif
   va_end(ap);
 
   if(s) {