Update SDL2 to version 2.28.1.

libs/SDL2/build-scripts/updaterev.sh

@@ -6,10 +6,40 @@ outdir=`pwd`
 cd `dirname $0`
 srcdir=..
 header=$outdir/include/SDL_revision.h
+dist=
+vendor=
+
+while [ "$#" -gt 0 ]; do
+    case "$1" in
+        (--dist)
+            dist=yes
+            shift
+            ;;
+        (--vendor)
+            vendor="$2"
+            shift 2
+            ;;
+        (*)
+            echo "$0: Unknown option: $1" >&2
+            exit 2
+            ;;
+    esac
+done
 
 rev=`sh showrev.sh 2>/dev/null`
 if [ "$rev" != "" ]; then
-    echo "#define SDL_REVISION \"$rev\"" >"$header.new"
+    if [ -n "$dist" ]; then
+        echo "$rev" > "$outdir/VERSION.txt"
+    fi
+    echo "/* Generated by updaterev.sh, do not edit */" >"$header.new"
+    if [ -n "$vendor" ]; then
+        echo "#define SDL_VENDOR_INFO \"$vendor\"" >>"$header.new"
+    fi
+    echo "#ifdef SDL_VENDOR_INFO" >>"$header.new"
+    echo "#define SDL_REVISION \"SDL-$rev (\" SDL_VENDOR_INFO \")\"" >>"$header.new"
+    echo "#else" >>"$header.new"
+    echo "#define SDL_REVISION \"SDL-$rev\"" >>"$header.new"
+    echo "#endif" >>"$header.new"
     echo "#define SDL_REVISION_NUMBER 0" >>"$header.new"
     if diff $header $header.new >/dev/null 2>&1; then
         rm "$header.new"