fix: Use #define instead of const int for VOBSUB_BLOCK_SIZE

MSVC doesn't support variable-length arrays (VLAs). The const int
declaration wasn't being treated as a compile-time constant,
causing Windows build failure with errors C2057, C2466, C2133.

Changed to #define which is a true compile-time constant.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: cfsmp3

src/lib_ccx/matroska.c

@@ -1427,6 +1427,7 @@ static void generate_vobsub_timestamp(char *buf, size_t bufsize, ULLONG millisec
 }
 
 /* VOBSUB support: Save VOBSUB track to .idx and .sub files */
+#define VOBSUB_BLOCK_SIZE 2048
 static void save_vobsub_track(struct matroska_ctx *mkv_ctx, struct matroska_sub_track *track)
 {
 	if (track->sentence_count == 0)
@@ -1504,9 +1505,6 @@ static void save_vobsub_track(struct matroska_ctx *mkv_ctx, struct matroska_sub_
 	snprintf(lang_line, sizeof(lang_line), "\nid: %s, index: 0\n", lang_to_use);
 	write_wrapped(idx_desc, lang_line, strlen(lang_line));
 
-	// Block size for alignment (2048 bytes = 0x800)
-	const int VOBSUB_BLOCK_SIZE = 2048;
-
 	// Buffer for PS/PES headers and padding
 	unsigned char header_buf[32];
 	unsigned char zero_buf[VOBSUB_BLOCK_SIZE];