misc: Correct various -Wunterminated-string-initialization warnings

-Wunterminates-string-initialization will complain if we try to shove
a "string" into a fixed array that is too small.  Sometimes this is
intentional; when you are merely using "string" as a standin for
"non-terminated sequence of bytes".  In these cases we need to mark
the "string" as "not actually a string" with an attribute.  Applies to
GCC >=8, but this warning isn't pulled in by -Wextra until GCC >= 15.

Change-Id: Ib94410a22f4587940b16cf03d539fbadc3373686

apps/plugins/doom/d_main.c

@@ -737,7 +737,7 @@ void D_DoomMainSetup(void)
    {
       // These are the lumps that will be checked in IWAD,
       // if any one is not present, execution will be aborted.
-      const char name[23][8]=
+      const char name[23][9] =
          {
             "e2m1","e2m2","e2m3","e2m4","e2m5","e2m6","e2m7","e2m8","e2m9",
             "e3m1","e3m3","e3m3","e3m4","e3m5","e3m6","e3m7","e3m8","e3m9",

apps/plugins/frotz/fastmem.c

@@ -199,7 +199,7 @@ void init_memory (void)
     static struct {
     enum story story_id;
     zword release;
-    zbyte serial[6];
+    zbyte serial[6] __NONSTRING;
     } records[] = {
     {       SHERLOCK,  21, "871214" },
     {       SHERLOCK,  26, "880127" },

apps/plugins/rockboy/save.c

@@ -29,7 +29,7 @@ struct svar
     int len;
     union
     {
-        char key_[4];
+        char _key[4] __NONSTRING;
         un32 key;
     } k;
     void *ptr;

apps/plugins/sort.c

@@ -56,15 +56,12 @@
 /***************************************************************************
  * TODO: Implement a merge sort for files larger than the buffer
  ****************************************************************************/
-
-
-
 size_t buf_size;
 static char *filename;
 static int num_entries;
 static char **pointers;
 static char *stringbuffer;
-static char crlf[2] = "\r\n";
+static char crlf[2] __NONSTRING = "\r\n";
 static int bomsize;
 
 /* Compare function for sorting backwards */

apps/plugins/sudoku/sudoku.c

@@ -527,11 +527,11 @@ static bool save_sudoku(struct sudoku_state_t* state)
     int i;
 #ifdef SUDOKU_BUTTON_POSSIBLE
     int x;
-    char line[41]="...|...|... ;                          \r\n";
+    char line[41] __NONSTRING ="...|...|... ;                          \r\n";
 #else
-    char line[13]="...|...|...\r\n";
+    char line[13] __NONSTRING = "...|...|...\r\n";
 #endif
-    char sep[13]="-----------\r\n";
+    char sep[13]__NONSTRING = "-----------\r\n";
 
     rb->splash(0, "Saving...");
 

firmware/export/config.h

@@ -1070,6 +1070,17 @@ Lyre prototype 1 */
 #define ROCKBOX_STRICT_ALIGN 1
 #endif
 
+/* -Wunterminates-string-initialization will complain if we try to shove
+  a "string" into an array that is too small.  Sometimes this actually
+  intentional, where you are merely using "string" as a standin for
+  "non-terminated sequence of bytes" -- in which case we need to mark
+  the "string" as "not actually a string" with an attribute.  Applies to
+  GCC >=8, but this warning isn't pulled in by -Wextra until >= 15.
+*/
+#if __GNUC__ >= 8
+#define __NONSTRING __attribute__((__nonstring__))
+#endif
+
 /*
  * These macros are for switching on unified syntax in inline assembly.
  * Older versions of GCC emit assembly in divided syntax with no option