Suppress Clang warning on adding an integer to a string

Suppress Clang warning on adding an integer to a string, like:

tst-iconv-sticky-input-error.c:125:42: error: adding 'int' to a string does not append to the string [-Werror,-Wstring-plus-int]
  125 |                 expected_output = "ABXY" + skip;
      |                                   ~~~~~~~^~~~~~
tst-iconv-sticky-input-error.c:125:42: note: use array indexing to silence this warning
  125 |                 expected_output = "ABXY" + skip;
      |                                          ^
      |                                   &      [     ]

Co-Authored-By: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Sam James <sam@gentoo.org>

dirent/tst-readdir-long.c

@@ -26,6 +26,7 @@
 #include <support/support.h>
 #include <support/xdirent.h>
 #include <support/readdir.h>
+#include <libc-diag.h>
 
 /* If positive, at this length an EMSGSIZE error is injected.  */
 static _Atomic int inject_error_at_length;
@@ -59,7 +60,10 @@ add_directory_entry (struct support_fuse_dirstream *d, uint64_t offset)
   if (offset <= 1)
     {
       type = DT_DIR;
+      DIAG_PUSH_NEEDS_COMMENT_CLANG;
+      DIAG_IGNORE_NEEDS_COMMENT_CLANG (13, "-Wstring-plus-int");
       name = ".." + !offset;    /* "." or "..".  */
+      DIAG_POP_NEEDS_COMMENT_CLANG;
       ino = 1;
     }
   else if (length == 1000)

dirent/tst-rewinddir.c

@@ -24,17 +24,21 @@
 #include <support/readdir.h>
 #include <support/support.h>
 #include <support/xdirent.h>
+#include <libc-diag.h>
 
 /* Return the file name at the indicated directory offset.  */
 static char *
 name_at_offset (unsigned int offset)
 {
+  DIAG_PUSH_NEEDS_COMMENT_CLANG;
+  DIAG_IGNORE_NEEDS_COMMENT_CLANG (13, "-Wstring-plus-int");
   if (offset <= 1)
     return xstrdup (".." + !offset); /* "." or "..".  */
   else
     /* Pad the name with a lot of zeros, so that the dirent buffer gets
        filled more quickly.  */
     return xasprintf ("file%0240u", offset);
+  DIAG_POP_NEEDS_COMMENT_CLANG;
 }
 
 /* This many directory entries, including "." and "..".  */

iconv/tst-iconv-sticky-input-error.c

@@ -26,6 +26,7 @@
 #include <support/support.h>
 #include <support/test-driver.h>
 #include <stdio.h>
+#include <libc-diag.h>
 
 /* FROM is the input character set, TO the output character set.  If
    IGNORE is true, the iconv descriptor is set up in the same way as
@@ -121,12 +122,15 @@ do_test (void)
           for (int skip = 0; skip < 3; ++skip)
             {
               const char *expected_output;
+	      DIAG_PUSH_NEEDS_COMMENT_CLANG;
+	      DIAG_IGNORE_NEEDS_COMMENT_CLANG (13, "-Wstring-plus-int");
               if (do_ignore || strstr (charsets[to_idx], "//IGNORE") != NULL)
                 expected_output = "ABXY" + skip;
               else
                 expected_output = "AB" + skip;
               one_direction (charsets[from_idx], charsets[to_idx], do_ignore,
                              "AB\xffXY" + skip, expected_output, limit);
+	      DIAG_POP_NEEDS_COMMENT_CLANG;
             }
 
   return 0;

posix/bug-regex24.c

@@ -1,6 +1,7 @@
 #include <regex.h>
 #include <stdio.h>
 #include <string.h>
+#include <libc-diag.h>
 
 #define str "civic"
 
@@ -45,11 +46,14 @@ do_test (void)
       {
 	int len = m[i].rm_eo - m[i].rm_so;
 
+	DIAG_PUSH_NEEDS_COMMENT_CLANG;
+	DIAG_IGNORE_NEEDS_COMMENT_CLANG (13, "-Wstring-plus-int");
 	printf ("m[%d] = \"%.*s\"\n", i, len, str + m[i].rm_so);
 
 	if (strlen (expected[i]) != len
 	    || memcmp (expected[i], str + m[i].rm_so, len) != 0)
 	  result = 1;
+	DIAG_POP_NEEDS_COMMENT_CLANG;
       }
 
   return result;