Fixed bug 3813 - gcc7 fallthrough warnings in SDL_iconv.c and SDL_pixels.c

src/stdlib/SDL_iconv.c

@@ -798,6 +798,7 @@ SDL_iconv(SDL_iconv_t cd,
             if (ch > 0x10FFFF) {
                 ch = UNKNOWN_UNICODE;
             }
+            /* fallthrough */
         case ENCODING_UCS4BE:
             if (ch > 0x7FFFFFFF) {
                 ch = UNKNOWN_UNICODE;
@@ -819,6 +820,7 @@ SDL_iconv(SDL_iconv_t cd,
             if (ch > 0x10FFFF) {
                 ch = UNKNOWN_UNICODE;
             }
+            /* fallthrough */
         case ENCODING_UCS4LE:
             if (ch > 0x7FFFFFFF) {
                 ch = UNKNOWN_UNICODE;

src/video/SDL_pixels.c

@@ -326,7 +326,7 @@ SDL_MasksToPixelFormatEnum(int bpp, Uint32 Rmask, Uint32 Gmask, Uint32 Bmask,
         if (Rmask == 0) {
             return SDL_PIXELFORMAT_RGB555;
         }
-        /* Fall through to 16-bit checks */
+	/* fallthrough */
     case 16:
         if (Rmask == 0) {
             return SDL_PIXELFORMAT_RGB565;